Sheldon Cooper

Sheldon Lee "Shelly" Cooper, B.S., M.S., M.A., Ph.D., Sc.D., is a Caltech theoretical physicist who shares an apartment with his colleague and best friend, Leonard Hofstadter. Originally from Texas, Sheldon started college at the age of 11, receiving his first Ph.D. at 16. Sheldon was involved in numerous experiments as a wunderkind, such as his plan to provide free electricity for his town by building a nuclear reactor - a plan stopped by government pen pushers claiming it's illegal to store yellowcake uranium in a garden shed! Unashamedly geeky, he has no qualms about speaking Klingon, wearing vintage t-shirts sporting superhero logos, or spouting various historical and cultural anecdotes (e.g., his account of the introduction of the fork into Thailand). While he might claim to be the perfect human specimen, Sheldon does have his faults. Appearing to have Asperger's Syndrome as well as Obsessive Compulsive Personality Disorder, Sheldon is characterized by: a strict adherence to routine; an overtly intellectual personality; a tenuous understanding of irony, sarcasm and humor; and a general lack of humility or empathy, the former of which is demonstrated in the fact that he has no problem voicing to his peers his admiration for his superior intellect. These qualities are his character's main source of humor and occasionally cast him as the primary antagonist of the series. He has been described as the show's breakout character.

Early Life
Sheldon was born in Galveston, Texas to Mary Cooper, a devout Evangelical Christian, and George Cooper, a Texan Homer Simpson who died quite a while ago due to an unknown cause. He has a twin sister named Missy Cooper and a brother named George Cooper, both described by their mother to be "dumb as soup." Sheldon was raised according to his mother's beliefs, e.g., learning how to pray and becoming the co-captain of the East Texan Christian Youth Holy Roller Bowling League Championship team, seven-to-twelve year-old division.

Like the typical nerd, Sheldon was bullied a lot as a child, mainly by his classmates, neighborhood kids and his siblings. Not so much because of his looks, but because of his expressing intellectual superiority to them and being a complete Smart Alec. He would get a lot of beatings from the neighbor kids and would get swirlies all the time, even in church. There were also noogies and wedgies. He would have some of his stuff taken away from time to time, like his lunch money or his kites. Luckily, he only had to cope with this until he was eleven, as he then went straight to college, but that didn't stop his siblings. Sheldon tells Amy Farrah Fowler, that his childhood was "hell". Further anecdotes reveal he built a so-called "Sonic Death Ray" that didn't even slow down the neighbor kids, and constructed a robotic arm, using homemade integrated circuits from silicon substrates cooked in his sister's Easy-Bake Oven which he modified, to defend his room from Missy.

Sheldon entered college at the age of eleven, right after completing the fifth grade. At age twelve, filled with disappointment at not receiving a titanium centrifuge to separate radioactive isotopes, he had to be flown to a hospital by helicopter to be treated for radiation damage following a mishap when he built a CAT scanner (which also resulted in the death of his sister's guinea pig, Snowball) and conducted experiments involving the height of stairs only to deduce that if a step on a staircase is two millimeters off or more, a person is likely to trip - his findings evidenced by his father breaking his clavicle. When Sheldon was thirteen, he attempted to build a nuclear reactor in order to provide free electricity for his town but it failed after a government agent informed him that it was illegal to store yellowcake uranium in a shed; he then had a big tantrum as a result. When Sheldon was fourteen years old, he graduated college summa cum laude, began doctoral work, and was the youngest person at the time to receive the Stevenson Award when he was "fourteen and a half." He received his first doctorate at the age of sixteen and he then spent four years on his second dissertation, before obtaining his current job.

Career
Dr. Sheldon Cooper is a senior theoretical particle physicist at the California Institute of Technology, focusing on string theory and its extension, M-theory. He has held this position for three-and-a-half years at the outset of the show. Previously, he was a visiting professor at the Heidelberg Institute in Germany at age fifteen and examined perturbative amplitudes in N=4 supersymmetric theories leading to a re-examination of the ultraviolet properties of multiloop N=8 supergravity using modern twistor theory at age sixteen. For his contributions to theoretical physics, he won a Caltech Chancellor's Award for Science.

Throughout the course of the show, Sheldon has switched disciplines from bosonic string theory to heterotic string theory, written a paper on the decays of highly excited massive string states, illustrated mirror symmetry in the footnote of a publication, determined that three-dimensional string-nets provided a unified picture of fermions and gauge bosons, made a breakthrough in showing how neutrinos emerge from a string-net condensate, reconciled the black hole information paradox with his theory of string-network condensates, designated time for solving the spacetime geometry in higher spin gravity, and worked on time-dependent backgrounds in string theory, specifically quantum field theory in D-dimensional de Sitter space. With Rajesh Koothrappali, he worked on the string theory implications of gamma rays from dark matter annihilations and considered a method for optimizing a 500 GeV particle detector to this end.

In the second-season finale "The Monopolar Expedition", Sheldon receives a grant from the National Science Foundation to travel to the North Magnetic Pole for an experiment in search of slow-moving magnetic monopole particles, with Leonard, Raj and Howard as his support team. In the experiment he detects what he believes is significant monopolar magnetic charge, validating one of the chief predictions of superstring theory. Though Sheldon publicly announces he has confirmed string theory and will receive a Nobel Prize, he learns that the charge detected was actually static electricity from the others' electric can opener, forcing Sheldon to issue a retraction to his announcement and severely damaging his reputation at the university.

Sheldon did work in quantum loop corrections, but he hadn't considered a Lorentz invariant field theory approach. However, he believes string theory better unites quantum mechanics with general relativity than does loop quantum gravity. He neither gives credence to the notion that quantized spacetime will manifest itself as minute differences in the speed of light for different colors (as he expects matter consists of tiny strings) nor that only loop quantum gravity calculates the entropy of black holes.

At a San Francisco conference, Sheldon tried to initiate a collaboration with Nobel Prize-winning physicist George Smoot by presenting him his paper on astrophysical probes of M-theory effects in the early universe. He also maintained a correspondence with cosmological physicist Dr. Elizabeth Plimpton for years about their mutual interest in gravitational wave signatures of inflatons in the early universe. When Caltech received a new open science grid computer, he attempted to schedule time to run simulations of structure formation in the early universe.

Sheldon has grappled with Gedankenexperiments (i.e., "thought experiments") to illustrate the quantum measurement problem. He produced four out of the five Gedankenexperiments he thought necessary for a cogent restatement of the quantum measurement problem, before the information was lost.

Sheldon also engages in condensed matter physics research on occasion and has lectured on topological insulators. With Leonard, he coauthored a paper entitled Paradoxical Moment-of-Inertia Changes Due to Putative Super-Solids, to be presented at an Institute for Experimental Physics topical conference on Bose-Einstein condensates. He discovered that electrons traveling through a graphene sheet on hexagonal pathways possess zero effective mass since they coincidentally exhibit the same dispersion pattern as fermions and must be considered as a wave. In addition, he had a minor epiphany regarding the polymer degradation phenomenon.

Characterization
Aside from his idiosyncrasies, Sheldon is logical. He possesses an eidetic memory and an IQ of 187, although he claims his IQ cannot be accurately measured by normal tests. Sheldon has an overly extensive general knowledge, such as shown by his comments regarding various details of anecdotal knowledge (for instance, about the introduction of the fork into Thailand).

Sheldon also has qualities associated with being a prodigy, such as an inflated ego, social ineptness, and an inability to relate emotionally with others. Despite his intelligence, he has a distinct lack of emotional maturity and is often baffled by even the most common social interactions. He not only fails to understand the simplest sarcastic jokes made by Leonard, but also regards Penny's sadness over one of her breakups with blatant confusion. However, recently, he has begun to understand the concept of sarcasm, attempting unsuccessfully to employ it himself towards Penny in the second season, and successfully employing it towards his friends in the third season. He appears to have a complete disinterest in romantic relationships, and his eccentricities, direct remarks, and demanding nature put him at odds with his own friends and especially Penny. Sheldon's expression of his more advanced intelligence has gotten him fired from his job, and even Leonard is surprised to learn that Sheldon is conceited enough to believe that Isaac Newton is intellectually inferior to himself. Sheldon hates it when someone stops him when he is trying to explain something. If this happens: a tic starts on his face until he can complete what he wants to say. He cannot and will not drive, and thus someone must always drive him. (Except when he drives Penny to the emergency room in "The Adhesive Duck Deficiency".)

He also has symptoms of obsessive compulsive personality disorder and Asperger's syndrome, e.g., when he finds Penny's apartment messy, he sneaks in during the night and cleans it up because he can't stand being in the same hallway with something so disastrous, he refuses to sit anywhere other than his designated spot on the couch and follow set routines, and the running gag of the show is that when he knocks on Penny's door, he has to say Penny's name every three knocks (he does this thrice everytime).

Sheldon occasionally uses slang (in a very unnatural fashion), and follows jokes with his catchphrase "Bazinga!". He is not entirely sure how to hug someone, and avoids human contact whenever possible. Despite his egocentricism, Sheldon appears to be somewhat aware of his social ineptitude, particularly his lack of understanding of sarcasm. He mentioned that he keeps a record of his daily conversations after Penny snapped at him and Leonard asked him why, to which he suggested that Leonard check his conversation records "to see if I messed up anywhere." Sheldon is also a difficult person to work with and generally displays apathy to the world around - in The Toast Derivation Sheldon criticised Bill Gates for focusing on his charity work rather than Windows Vista, a remark that earned him a punch in the face from Gates.

Childlike Qualities
Sheldon also possesses many childlike qualities. For example, even though he is unaware of it, Sheldon is extremely stubborn. Examples of this include naming the Caltech Physics Bowl team or deciding to go to San Francisco by train instead of flying (due to his fascination and love of trains), and his needing of his mother (or Penny) to care for him when he is sick, which involves singing "Soft Kitty" and rubbing Vicks on his chest. He cannot stand to be interrupted, concede when he doesn't know something, or hear people bicker or argue, crinkling his lips with intense frustration when any of these events occur. Sheldon has not attempted to obtain a driver's license (although he does possess a learner's permit), and needs his friends to drive him everywhere; he refuses the bus. He attempts to learn to drive on a simulator, however he fails the moment it starts. Sheldon's defense is that he is "too evolved" to perform plebian tasks; driving.

In Season 5's "The Pulled Groin Extrapolation", Amy asked Leonard to attend a wedding with her. Leonard asked why she did not ask Sheldon to go instead. Amy answered that Sheldon behaved like a child the last time so he is out. After Amy left, Sheldon said in a sing-song tone to Leonard; "heh heh, you have to go to a wedding!" as he was unwrapping his newly-bought toy train set, further emphasizing his childlike qualities.

However the majority of these problems can be traced back to his root personality fault of stubbornness, which many fans believe is because of Aspergers or OCD.

Interests
Like his friends, he is scientifically inclined, and is fond of comic books, costumes, video games, and science fiction, specifically Battlestar Galatica, Doctor Who, Stargate, Star Trek, Star Wars, and Firefly, although he strongly dislikes Babylon 5. He has claimed to be an honorary graduate of Starfleet Academy, and is an avid fan of science officer Spock. Other favorite characters of his are Batman, The Flash and The Green Lantern.

He likes playing Halo every Wednesday and paintball on the weekend with his friends. He can also play the piano and theremin, and seems to be a very good Tuvan throat singer, but would be better if not for a part in the roommate agreement denying him practice.

Sheldon often wears vintage T-shirts adorned with superhero logos specific to the DC universe, among them the Flash, Superman, Aquaman, and the logos of the various Lantern Corps. He usually wears a long sleeve shirt underneath it along with plaid pants. Sheldon is tall and thin (setting him apart from his shorter colleagues), with Penny, and later Leonard, saying he looks like a giant praying mantis.

Drugs and Alcohol
With few exceptions, Sheldon refuses all drugs, including alcohol and caffeine, as a promise to his mother. In addition, when Penny mixed alcohol into his drink, he began to play the piano and sing To Life in front of an audience. A small amount of coffee made him extremely hyperactive but unproductive in another. Taking valium also affected his behavior. Probably the most infamous time of him being drunk was when he had to give a speech in "The Pants Alternative" and he acted like a comedian due to the abundance of wine he drank to calm his nerves. The scene was uploaded on YouTube where it is revealed Sheldon also took off his pants and mooned the audience.

While it is argued that Sheldon drank beer in the Pilot, it could have also been orange soda.

Softer Side
Despite his strange behavior, Sheldon has, at times, demonstrated a much softer side to himself. However, these moments are rather rare and, more often than not, he only shows his caring side towards Penny. In one instance, when Penny was low on money, Sheldon let her borrow a large amount of his savings, but while she worried about paying it back, he was entirely unconcerned as to when he got it back. This was later described by Leonard as "one of the few idiosyncrasies that doesn't make you want to, you know, kill him". Also, after Penny let him stay at her place when he locked himself out of his apartment, Sheldon sincerely thanked her for it. When Penny gave Sheldon a Christmas present, he was extremely anxious because he did not know what it was and therefore did not know how to reciprocate. He purchased multiple gift baskets of bath items (in order to choose one which matched the value of her gift), only to find that she got him a napkin autographed by his idol, Leonard Nimoy, (which he had also wiped his mouth with, and therefore had his DNA on it). This prompted him to give her all the baskets and a hug (the first time he has shown any physical intimacy with anyone). When Penny fell and dislocated her shoulder, Sheldon spent the entire night taking care of her, including driving her to the hospital despite the fact that he does not know how to drive. He finished the night by helping her into bed and singing soft kitty to her after she asked him too. He also hugged Penny again when she said she would talk to Leonard about having him take Sheldon to Switzerland rather than her. This prompted him to sincerely thank her and hug her. With the exception of his family, Penny, Wil Wheaton and Amy Farrah Fowler are the only people Sheldon have hugged, with the latter he specifically cuddled with in Season 5 Episode 8's The Isolation Permutation episode, when after a discussion to console a weepy Amy who was craving for human intimacy and physical contact. After turning down Amy's proposals of getting into bed together and french-kissing, Sheldon agreed with her final offer to cuddle, though he got upset over it later, by yelling to Leonard and Howard to keep Penny and Bernadette in line and have them apologize to Amy since consoling Amy had caused him to miss the time he had designated to solve Spacetime Geometry in Higher Spin Gravity and building his Lego Death Star. This particular event of him cuddling with Amy Farrah Fowler is a huge development of his personality since he is not shown to have much empathy or sympathy on others but he was able to tolerate Amy's situation, despite the awkwardness of the experience and his lack of willingness to actually do so in the first place.

Religion
In contrast to his profoundly religious mother and devout Christian upbringing, Sheldon has no interest in religion - he tends to ignore or express dislike for religious celebrations such as Christmas, and wastes no time in bringing up the Pagan origins to each festival. Additionally, his scientific beliefs often come into conflict with the spiritual beliefs of his mother, Mary. Nevertheless, he has an agreement with his mother to attend church once a year, and once exclaims "Thank you, Jesus!" upon getting a strike in a bowling match against Wil Wheaton (his arch-enemy).

Adherence to Laws
Sheldon also appears to have problems understanding societal laws at times. He is shown to drop objects out his window into traffic without regard, in addition to breaking into buildings. He has expertise with picking locks and disarming alarm systems. Furthermore, the Department of Homeland Security notifies his mother when he acts contrary to federal law. As he states later, "Apparently you can't hack into a top-secret government supercomputer and then try to buy uranium without the Department of Homeland Security tattling to your mother." This implies that Homeland Security is familiar with him, as instead of arresting and questioning them, they simply inform his mother and have her deal with him.

Asperger's syndrome
Though Sheldon has never been confirmed as having Asperger's syndrome, many of his traits and much of his behavior exemplifies it. These qualities include social ineptitude, a lack of empathy, obsessive–compulsive personality disorder, and many more traits which make him the most eccentric and bizarre of the characters in the show. Many of these traits are the reasons why Leonard finds him hard to live with and his friends find him so hard to be around. These include:


 * Obsessive–compulsive personality disorder: Sheldon exhibits a strict adherence to routine, such as doing specific recreational activities on specific days of the week, going to the bathroom on a specific time every morning, eating specific food items on specific days, being unable to reconcile changes to food orders, doing laundry on a specific day and time (every Saturday night at 8:15), or knocking on the door a certain number of times while repeating the name of the person he is seeking with a particular frequency ("[knock knock knock] Penny [knock knock knock] Penny [knock knock knock] Penny" being the most common.) Amy Farrah Fowler notifies this to Sheldon as a symptom of Obsessive Compulsive Disorder and she finds he is in denial over it. Sheldon labels all home utensils, appliances, etc., including his labelmaker. He also makes loud noises (or musical notes with a xylophone) in every theater before a movie, attempting to locate the "acoustic sweet spot". However, he can adapt to seats with sub-optimal conditions, such as suitable cushion densities and light dispersion, provided he has the opportunity to test them.
 * Narcissistic personality disorder: Though not technically meeting all or enough requirements for a formal diagnosis, Sheldon constantly points out his superiority among his friends.
 * Mysophobia: He is constantly worried about others touching his food, washes his hands as often as he can, and showers twice daily. Leonard used his concerns for food to mock him in "The Einstein Approximation", as did Raj in "The Engagement Reaction". Penny has stated that he still has not learned to not to insult those who handle his food, to which Amy Farrah Fowler agrees.
 * Hypochondriasis: He is extremely worried about becoming sick. He became worried about Penny infecting him with influenza and subsequently contracted it. Another time, he wanted a full medical examination by Leonard's girlfriend, Dr. Stephanie Barnett, in order to discover the cause of a high-pitched noise in his head. When Howard's mother is sent to the hospital, Sheldon refuses to go due to exposure to pathogens and germs, until Penny confronts him. Though, he accidentally wanders into a biohazard room at the hospital, after fearing the restroom's cleanliness, and endures a two-week quarantine. Sheldon showers twice a day and washes his hands as often as he can. In addition, Sheldon has a red toothbrush that is kept in a Plexiglass case under a UV lamp.
 * Inability to lie: When Sheldon is complicit in a lie, he exhausts all of his efforts in his almost always unsuccessful attempt to make it believable. Similarly, he cannot be entrusted with a secret because he develops nervous tics. However, it is easier for him to lie if he has prior knowledge of the deception or an "ironclad alibi" thought out in advance, as opposed to it being "impromptu dishonesty".
 * Intolerance of people in his bedroom. One time, he was distraught when Penny entered his room in the middle of the night. On another occasion, Sheldon hesitantly let Penny in his bedroom to get a key for his desk to retrieve a USB flashdrive, constantly reminding her that, far from creating a permanent easement, it was only one-time permission.
 * Stage fright: While perfectly comfortable speaking to small groups, Sheldon cannot speak to crowds deemed large enough to trample him (36 adults or 70 children) without having a panic attack.

He also keeps a record of what he considers faux pas "strikes", which he allocates to those who violate his self-imposed conditions. Upon receiving three strikes, Sheldon gives them the choice of either apologizing or taking a "class". For many of the characteristics aforementioned, Sheldon's friends often consider him "insane" or "crazy" despite Sheldon's repetition of another catchphrase "I'm not insane/crazy! My mother had me tested." Despite Sheldon's personality disorders and difficult habits, his friends usually just do what he says because it is easier. It has also been revealed that Sheldon has a bifurcated uvula, something which he is self-conscious about.

Sheldon's Spot on the Couch
{C The most notable feature of Sheldon's obsessive-compulsive disorder is his refusal to sit anywhere other than his designated spot on the far left cushion of the couch in his apartment, which he considers his "single point of consistency in an ever-changing world" and "the singular location in space around which revolves my entire universe", exceeding his love for his mother. He describes his spot on the couch as being his point 0, 0, 0, 0 if his life were a Cartesian coordinate plan. Sheldon regularly reproaches Penny and other people for sitting in his spot. Even disruptions to this location are enough to disturb him. Although he did allow Penny to sit in his spot in the first episode, as well as Howard, for a short time in "The Apology Insufficiency", only 94 seconds later he reclaims his spot. As well as his designated spot in the apartment, if Sheldon is ever in a different area where he is going to sit down, such as Penny's apartment, he has to choose the best sitting location based on such things as optimal television viewing, lighting, airflow, and cushion density.

Quotes

 * "Bazinga!"
 * —Quote when he makes a joke
 * "(knock x 3) Penny! (knock x 3) Penny! (knock x 3) Penny!"
 * —Quote from various episode whenever he knocks on the door of Penny's apartment.
 * "That's no reason to cry. One cries because one is sad. For example, I cry because others are stupid, and it makes me sad. "
 * —Quote from The Gorilla Experiment
 * "On the contrary. I find the Grinch to be an engaging and relatable character, I was right with him right up until he succumbs to social convention and returns the presents and saves christmas. What a buzzkill that was."
 * —Quote from The Maternal Congruence
 * "I'm attempting to view my work as a fleeting peripheral image so as to engage the superior colliculus of my brain. "
 * —Quote from The Einstein Approximation
 * "How can someone think we're going to blow up the moon!?! that's a good question. "
 * —Quote from The Lunar Excitation
 * "WHEATON......................................................................................................!"
 * —Quote from various episodes, usually after Wheaton messes with him
 * "I am not crazy, my mother had me tested."
 * —Quote from various episodes, always said after someone calls him crazy.

Relationships
Of all main characters of the show, Sheldon is presumed to be asexual and has displayed the least interest in pursuing a sexual relationship with ANYONE. He tries to avoid all human physical and emotional contact. He has, however, had a few opportunities to "get it on" - maybe more opportunities than the other characters. Being true to his personality though, he never seems to realize it. However, the introduction of Amy Farrah Fowler into the show has changed this aspect of him, at least slightly. Even though Amy is a girl, who is his friend but is not his girlfriend, she is the closest person who may be romantically-linked to Sheldon though at this point, their relationship is nothing more than as of friends of as Sheldon put it, "a relationship of the minds".

Penny
Despite Penny not being a knowledgeable person nor sharing many of the group's interests (Parsons described the characters as "polar opposites"), and having constant fights with Sheldon in the early episodes, they became close friends, due to some time alone with each other, such as when Penny cares for Sheldon during illness or when Penny takes him in when he is locked out of his apartment while his friends are in Las Vegas. Sheldon returns the favor as he cares for Penny when she dislocates her shoulder. In all of these instances, the story line ends with one of them singing "Soft Kitty," a song Sheldon's mother used to sing to him when he was sick. On the one hand, Sheldon and Penny spend a lot of time getting on each other's nerves: Sheldon often mentions how uneducated or untidy Penny is, while Penny likes to irritate him by sitting in his spot, messing with food, and they once started a futile war (Penny blocked Sheldon from doing his laundry on his laundry day, and he responded by exposing her clothes and underwear outside the window). However, they also efficiently team up, for example to plan Leonard's birthday or to develop Penny's "Penny Blossoms" business, singing along to sailors songs to motivate each other. They end up spending a lot of time together as two close friends to help each other and give each other advice (Penny helping to find a suit for Sheldon for an awards ceremony, or seeking Stan Lee's address for him because he couldn't meet him as the other members of the group did; Sheldon teaching Penny physics to help her in her relationship with Leonard). On a few occasions, they also appear to share a sort of intimacy that Sheldon doesn't have with anyone else: they both take care of each other when they don't feel well; they stayed together in the flat, cranky and grumpy, as they had both caught the flu after a hug they had exchanged; Sheldon has an immediate, very nervous and alarmed reaction when he hears Penny calling for his help from her flat; they sing together "Soft Kitty" as a round in a kind intimate moment; Sheldon adds an amused "Bazinga" to one of Penny's jokes, to which she replies with a tender "Hmm..."

Sheldon acknowledges Penny as one of his closest friends (along with Leonard and Raj), while he considers that Howard is a "treasured acquaintance," though he has known him a lot longer than Penny. Also, when Penny and Leonard break up, Sheldon still considers Penny a friend and makes dinner plans, which he tries to hide when Howard informs him that it is inappropriate behavior and "bros come before ho's." He actually goes through a lot of trouble (hiding frozen hot dogs in his pants, confronting a huge threatening dog ... ) just to dine with her, though he's already been forced to eat a whole meal with the boys. In the end, Leonard and Penny in a way share custody of Sheldon, taking him to Disneyland and out to buy new shoes.

The interaction between Sheldon and Penny has been praised by critics. James Chamberlin of IGN wrote: "Cuoco and Parsons are great in their own right, but when put together, they truly shine." Matt Roush of TV Guide said that Sheldon and Penny's "scenes and episodes together are usually Big Bang at its best." Todd WanDerVerff of The A.V. Club wrote that they "made such an inspired odd coupling that at times, it seemed as though the entire show were about them" and their chemistry "has some of the rattle and rhythm of the great comedic duos".[73] Chuck Lorre stated that Sheldon and Penny have "become a natural comic pairing" and they "bounce off each other beautifully."

Leonard Hofstadter
Sheldon is the best friend of Leonard, as they live together and are accustomed to tolerating each other ever since Sheldon put out an ad for a roommate with a list of criteria to follow. Despite Sheldon sometimes making remarks to the contrary, he appreciates Leonard and assures Leonard that his friend will not die alone. When Penny asks Leonard why he deals with Sheldon, he explains that Sheldon has actually saved his neck a few times, such as when he stopped him from being incinerated by his own improperly formulated rocket fuel and didn't tell on him to the landlord, the police or the Department of Homeland Security. This incident also lead to the destruction of the elevator, as Sheldon had just enough time to put the explosive contents of the container into the elevator before it exploded. Leonard also, more than all of Sheldon's other friends understands him the most, as viewed in many scenes where when all hopes failed to get Sheldon to participate in something, Leonard will be the last resort to come up with something successful. When Penny and Sheldon had a spat due to Penny sitting in his spot and touching his food and later refused to apologize to him, which resulted her being banished from the apartment, Penny came up with her own set of revenge, including banishing Sheldon from the Cheesecake Factory and messing up with Sheldon's Laundry Night. When things got really ugly between the two, a fed up Leonard secretly gave Penny Sheldon's mother's number, telling her it is Sheldon's Kryptonite. The feud ended after that, with Sheldon, clueless to the fact that it was Leonard who helped Penny, told Penny that she played well. Another instance was when Penny tried her hands at opening her own business by selling Penny Blossoms. When they had to stay awake all night to help Penny meet her order, a sleepy Sheldon refused coffee and decided to head to bed instead, leaving the rest to finish up by themselves. A frustrated Penny looked on to Leonard to do something and Leonard did, by saying to Sheldon that without his insight and leadership this entire enterprise will surely fail, which prompted Sheldon to change his mind and drink coffee.

Rajesh Koothrappali
Sheldon and Raj's relationship is rather complicated. Sheldon once offered help to Koothrappali by giving him a job under his supervision, which Raj reluctantly accepted to save him from getting deported back to India. Raj is easily annoyed with much of Sheldon's antics, but has grown accustomed to them. Before the boys went with Sheldon on the Arctic Expedition, Raj explained to Howard that the reason he puts up with Sheldon is because of his religion; 3 months of suffering at the Arctic Circle with Sheldon would mean he (Raj) would be reborn in the next life as 'a well-hung billionaire with wings'. Raj, as much as he hates Sheldon's opinions on every certain situation and his behaviour, considers Sheldon as a good friend.

Howard Wolowitz
Sheldon and Howard's relationship is purely existent, albeit extremely complicated. Sheldon often makes fun of Howard for not having a Doctorate. In "The Apology Insufficiency", Sheldon angers Howard by revealing details to the FBI that prevent him from obtaining a much needed security clearance. Howard refuses to accept Sheldon's apology, until Sheldon gives Howard his spot on the couch, prompting Howard to forgive Sheldon. Howard, much like Raj and Leonard are quite unused to his inflated ego. On the other hand, he and Sheldon are shown to get along well - He tried to help Sheldon drive on a simulator he created, and did help with Howard's creations. Nevertheless, the relationship between the two has its ups and downs.

Lalita Gupta
Lalita was arranged to be married to Raj. They went on a date together which gradually deteriorated as alcohol made him obnoxious. When Sheldon arrived at the bar, he thought she looked similar to an Indian fairytale princess from a bedtime story his mother used to read to him when he was sick. When he told her, she was flattered and ended up dumping Raj and going out for dinner with Sheldon. When he was asked about it the next day, he simply said that they ate and discussed dental hygiene. He didn't seem to realize that he technically was on a date with her.

Ramona Nowitzki
Ramona was a huge admirer of Sheldon and had an obvious crush on him, which he didn't seem to notice. In The Cooper-Nowitski Theorem, she asked him out for dinner at his apartment. After that, she began spending more and more time with him, preventing him from doing anything recreational like playing Halo, paintball or watching Battlestar Galactica so he could focus on his work. Eventually, he made a breakthrough. When she suggested they share credit, he simply responded "Get out!", after which she angrily left.

Martha
When Raj brought Sheldon to a faculty mixer to act as wingman, they picked up a girl named Abby and her friend, Martha, brought them to Sheldon and Leonard's apartment and played Rock Band with them. While Abby and Raj hit it off, Martha became interested in Sheldon. The two enjoyed a few stimulating discussions together at their second meeting, during which Raj and Abby "[got] busy," Martha visited Sheldon's room in the middle of the night and asked to come in, hoping for sex. Misinterpreting this, Sheldon went to sleep in Leonard's room and left Martha alone in his. She apparently lost interest in him after that.

Amy Farrah Fowler
Sheldon first met Amy via a dating site where Howard and Raj sneakily set up an account for him in the season 3 final, "The Lunar Excitation". Eventually, they found a perfect match for him and agreed to meet her at a cafe. When they told Sheldon, he refused to do it, believing dating sites to be "hokum". However, he was blackmailed into doing it when Raj said he had hidden a dirty sock in Sheldon's room and wouldn't remove it unless Sheldon went on the date. When they arrived, Sheldon had doubts until he met Amy, who acted exactly like Sheldon. She only agreed to come on the date as she and her mother have an agreement that Amy would date at least once a year. Sheldon noticed they had a lot in common and brought her a beverage of Tepid water. Raj and Howard regretted what they had done, with Howard saying, "Good God, what have we done?".

In the season 4 premier, "The Robotic Manipulation," Sheldon reveals that he has been talking to Amy for a few months online, after they first met. Penny is amazed that Sheldon has a girlfriend and Howard and Raj call Sheldon and Amy, "Shamy." But Sheldon denies that Amy is his girlfriend and mainly talk about Sheldon's theoretical physics, Amy's neurobiology and the possibility of having a child together via in-vitro fertilization. Penny convinces Sheldon to go on a proper date with Amy first, before he actually decides to have a child. Penny eventually ends up on the date with them, as she had to drive them to the restaurant. Whilst there, Penny tries to make conversation, but fails, while Amy and Sheldon calculate the number of men Penny would have dated. He ends up with 193, with 31 sexual encounters. Amy then asks if Penny feels like a "slut" and reveals that she has had 128 sexual encounters (if you include stimulation of the brain to induce orgasm).

Eventually, Penny convinces Sheldon to not have a child with Amy after threatening to tell his mother. In episode 3 of season 4, Amy and Sheldon break up for a period of time after an argument over their fields and which one is better than the other. This results in Sheldon buying a clowder of cats, which worries Leonard. So he calls Sheldon's mother, who is unusually surprised at what she sees with Sheldon. She then calls Amy and then does a technique of reverse psychology which Leonard instantly picks up on, but Sheldon is completely oblivious to. She tells Sheldon that it was a good thing he and Amy broke up because they are completely incompatible. Sheldon is instantly offended, so to prove his mother wrong, he offers Amy to reconcile, which she agrees after a negotiation on the amount of responsibility Sheldon has to accept for the break up (Amy offered 80%, Sheldon countered with 40%, settling at 65%).

Afterwards, Sheldon and Amy give away $20 to anybody willing to adopt a cat. In episode 5 of season 4, Amy requests Sheldon to meet her mother, which terrifies him and tries many ways to avoid her, as he thinks it's another step in their relationship. However, Amy says it is for her mother and not for her, as she only wants to be just friends with Sheldon and wants to pretend to be Boyfriend/Girlfriend to please her mother. Sheldon freaks out Amy's mother a bit, which was what Amy wanted her to be, when they tell her about their "fake" sex life. Her relationship with Sheldon is complex; it began as a purely intellectual friendship which consisted solely of text messaging, but, at some urging from Penny, eventually developed into a platonic friendship with dynamics similar to a romantic relationship, although not sexually intimate.

They later pretend to have had a sexual encounter (the made-up details of which included Amy becoming pregnant) as an experiment to see how long it would take the gossip to spread throughout their social circle, which Sheldon notes was "less than 24 hours." In The Agreement Dissection, she became drunk during a "girl's night" with Penny and Bernadette, at which Sheldon was present to escape Priya, and danced with Sheldon, after which Sheldon walked her home. She invites him in and, after advising him on how to deal with Priya, flirts with and then kisses Sheldon to which he responds "Fascinating". After she throws up and passes out, Sheldon puts a towel under her head as a pillow and leaves (but before doing this he regulated Amy's kitchen timer, which was making him go crazy).

The next morning, a hungover Amy video-calls Sheldon, and he informs her of the kiss, and when Amy admits she is unsure where to go from there, they agree to pretend the entire events of the evening never occurred.

Later, she invites Leonard to a wedding, explaining that she'd invited Sheldon before, but he "acted like a child." She and Leonard end up having a rather good time, though by the end of the night he'd sprained his groin dancing the Hokey Pokey and she's convinced he's in love with her. However, when Leonard tells Sheldon about the night, the way he describes it makes it seem as though he and Amy had sex. Sheldon bops Leonard rather hard on the shoulder, and states very firmly that Amy is not Leonard's, leaving his friend totally confused.

In The Isolation Permutation, Amy got depressed after Penny and Bernadette went bridesmaid dress shopping without her and Sheldon ended up comforting her, first, she asked for sex due to wanting physical intimacy and the couple made counter offers and settled with cuddling, something Sheldon could not stand doing.

A recurring topic for discussion among audience of the show is whether Amy may be the first person that Sheldon may have developed romantic feelings for, though he himself may not have realized it yet. It is clear that Amy is attracted to Sheldon, as witnessed in her many attempts to have some form of physical contact with him, such as kissing him while she was drunk, holding his hands and said that it was an experiment, and during the counter offers, she attempted to get Sheldon to agree to get into bed with her and french-kissing. Amy had also, in a scene in Season 5's "The Pulled Groin Extrapolation", told Leonard at a wedding that she has "a kinda-sorta-boyfriend playing with a model train and you don't hear me bitching about it", a clear reference to Sheldon. In "The Ornitophobia Diffusion", when Sheldon finally overcame his fear of bird and appeared infatuated by the bird, to the point he called him his little "Lovey-dovey", a slightly jealous Amy replied "guess you gotta have hollow bones to get some sugar around here".

Sheldon, while his feelings for Amy remains ambiguous, clearly cares for her at least. In "The Isolation Permutation", several events highlighted his care for Amy. When a devastated Amy wanted to be alone and did not respond to any form of communications Sheldon attempted to reach her, Sheldon grew worried and distracted, till Leonard suggested that they go over to her place to check up on her. While getting ready to leave their apartment, Sheldon shared a news that a bob cat was spotted near Amy's place and Leonard responded that he does not think that Amy has been eaten by a bob cat. A shocked Sheldon said that he was only sharing a piece of news and now, thanks to Leonard, he is worried whether Amy has indeed been eaten by a bob cat. Later, at Amy's apartment, when she told Sheldon that she wanted to be left alone, Sheldon asked, rather awkwardly whether Amy would like to talk about what's troubling her, though he did add that he has no problem if Amy says no. Afterwards, when Amy counter offered with him regarding human intimacy and physical contact, Sheldon eventually agreed to cuddle with her. When a drunk Amy called Sheldon as he was building his Lego Death Star, he and Leonard went to see her at the parking lot near the licquor store when she called Leonard "Lil' Leonard" and Sheldon "Cuddles", a term which earned a frown from Leonard. Sheldon quickly retorted with "Yes Cuddles, we cuddled, grow up Leonard", showing that he no longer cares about what his friends may say regarding his relationship with Amy.

Recent Family History
Sheldon had an extremely odd childhood. Twenty-nine years ago, Mary Cooper, a devout Christian living in Galveston, Texas, gave birth to her son Sheldon in a K-Mart. Leonard Hofstadter called her Sheldon's "Kryptonite."

Sheldon also has a fraternal twin sister, Missy Cooper, a hostess at Fuddruckers. Tall and attractive, she caught the attention of Leonard, as well as of Rajesh Koothrappali and Howard Wolowitz. Sheldon believes that within Missy's eggs lays the potential for another "superior mutation" like himself, and on this grounds considered his friends unsuitable to be with his sister. Sheldon became offended when he found that Missy tells others he is a rocket scientist; he apparently thinks the title is inaccurate and below him, telling her she might as well say he is a toll collector at the Golden Gate Bridge. (Wolowitz is a rocket-scientist)

Along with Missy, Sheldon also had an older brother, named George Jr. who often beat him up, along with Missy. Mary described the two of them as being "dumb as soup."

Sheldon's father, George, an almost-redneck Texan Homer Simpson, died recently, and Missy visited Sheldon to bring paperwork regarding their father's estate. Sheldon recalls that his father would force him to watch football despite his lack of interest for the sport. He also taught him archery which gives Sheldon an odd smell of K-Mart bourbon whenever he plays it, including the Wii version.

Sheldon is also very close to his grandmother, whom he calls "Meemaw," who in turn calls him "Moon Pie." Her name is not yet revealed so far.

Sheldon has a maternal uncle, Edward Cooper, who is called "Stumpy" as the result of a time when he cleaned a woodchipper by hand. Sheldon had an uncle, called Carl Cooper, who was killed by a badger whilst cleaning a chimney.

Sheldon's eating habits
Consistent with his characterization, Sheldon has many detailed and routine eating habits. He prefers his chicken diced, not shredded with low sodium soy sauce and spicy hot mustard, also brown rice instead of white. He loves to eat at Big Boy, an American restaurant chain, but eats at the Cheesecake Factory on Tuesday nights (presumably before the occasional Klingon Boggle game), which replaces eating at Big Boy (which then moved to Thursday until they had pizza on that day. Sheldon most likely eats at Big Boy whenever, or on special occasions.) Sheldon eats Giacomo's pizza on Thursday with sausage, mushrooms, and light olives. In The Agreement Dissection, however, Sheldon mentions that they used to order from a restaurant called Franconi's, which went out of business, forcing them to switch to Grazziano's. Sheldon sorts his cereal numerically by fiber content, and rewards himself with "Honey Puffs" cereal.

Sheldon neither drinks coffee, nor alcohol, because he promised his mother that he wouldn't start doing drugs while he resided in California. Instead he likes drinking diet Coke®. When forced to order a cocktail, Sheldon solves the problem by ordering a "virgin Cuba Libre," which is nothing more than a Coke® in a tall glass, served with a lime wedge. He then goes on to ask if Penny would make it diet. Sheldon likes Chinese food, and is adamant that the number of dumplings can be evenly split between all partakers of the meal, and always wants it from the restaurant Szechuan Palace. Sheldon even learns Mandarin to confront the restaurant when he believes they have been passing off orange chicken as tangerine chicken.

Sheldon eats Thai food on Mondays - Mee Krob with extra peanuts. Sheldon thinks chocolate pudding is the best type of pudding, and does not believe that three-tined forks are, in actuality, forks, but tridents, and refuses to eat with them. Sheldon doesn't like to go to the cinema if he can't eat Red Vines or drink Icees during the movie, and only if someone comes with him, so that he/she can give him the Heimlich Maneuver in case he chokes on popcorn. On the matter of Icees and Slurpees, Sheldon maintains that the two are wholly different. Sheldon always eats oatmeal for breakfast on Mondays, and always has French Toast for breakfast on certain days. Sheldon drinks herbal tea, sometimes with honey. His favorite flavor appears to be chamomile. Sheldon drinks hot chocolate only in the months containing the letter "R" (January, February, March, April, September, October, November, December) explaining "What is life without whimsy." Sheldon dislikes haggis and blood pudding. Sheldon believes that real Chili isn't supposed to have beans in it. Like Leonard, Sheldon hates Greek food, saying lamb kebab is "little cubes of charred meat that tastes like sweat".

Routines
Sheldon has many routines which he follows strictly. His morning routine is to wake up at 6:15 every Saturday, he pours himself a bowl of cereal, adds a 1/4 cup of 2% milk, sits down in his spot on the couch and turns on BBC America and watches Doctor Who. If he cannot complete this routine for some reason, he becomes very distraught. In addition, Sheldon goes to the Comic Book Store every Wednesday so he can see all the new comics on "New Comic Book Day." Also, every Wednesday night is "Halo Night", and Sheldon makes a big fuss about not starting at exactly 8:00pm and he must have the exact amount of time to play the game or else he takes the time out of eating or bathroom time. Sheldon does his laundry every Saturday night at 8.15 p.m. and uses a FlipFold to fold his t-shirts and socks. Each day, Sheldon has a specific pajama to wear. In the case of a stain, he still would not swap a pajama. He would rather sleep without bottoms as seen in The Barbarian Sublimation, when he spilled grape juice on his bottoms. Sheldon hates it when people change the contrast of the TV settings, talk to him through the bathroom door, change Band-Aids in front of him, buy generic ketchup, forget to rinse the sink, adjust the thermostat, or cook with Cilantro and mock trains.

Technology preferences
Being a scientific genius, Sheldon is very particular about his technological devices. Early on in the series, he uses what seems to be a customized Dell XPS 17. After being robbed, he adopts an Alienware M17x Nebula Red laptop that runs on Windows 7, which he doesn't like as it is more user friendly than Window Vista. Sheldon's favorite Linux-based Operating System is Ubuntu. Sheldon has an iPhone 4, and he and his friends enjoy making fun of the Apple Genius Bar employees.

Video Games
Sheldon and his friends play Age of Conan where he is a Conqueror by the name of Sheldor the Conqueror and has reached Level 80. Sheldon and all of his friends play numerous multiplayer online games; he is a Blood Elf Warlock (though it is originally stated he is a Night Elf Rogue) in World of Warcraft, loves Super Mario Bros. (wanting to control people in the same way he can control Mario in the video game Super Mario 64), and plays Halo every Wednesday night with his friends. He also plays bass guitar in the video game Rock Band. When Sheldon plays Wii archery, he likes to do it like in real life, including drawing an arrow out of a quiver because he believes the people at Nintendo can go so far as to help people recreate an actual athletic experience and they need to do their part too. Sheldon is not good at Mario Kart on Wii. Raj points out, that in real life or in games, he cannot drive. Sheldon is, however, very good at bowling on Wii Sports (and real life).

Movie preferences
Sheldon's favorite Star Trek movie is: Star Trek IV: The Voyage Home. He also likes the movie Saturn 3, and Star Wars, but thinks the latest stuff by George Lucas is not so good. Sheldon's favorite actress playing Catwoman in the Batman movies is Julie Newmar, followed by Michelle Pfieffer, Eartha Kitt and Lee Merryweather with his least favorite being Halle Berry, although he says she made a fine Storm in the X-men movies.

Trivia

 * Sheldon is 31 years old. In The Russian Rocket Reaction, he reveals he was 9 years old when he started his all-time enemies list on a 1989 floppy disk. This age is further supported by Leonard's comment that Sheldon has been emotionally stuck for about 29 years in The Einstein Approximation.
 * According to Mary Cooper (Sheldon's Mother), Sheldon has her eyes, but has his daddy's temper and all that science stuff comes from Jesus.
 * According to Sheldon, he says that his mom wants grandchildren from Sheldon, but Penny adds that she wouldn't want a test tube grandson born out of wedlock (this being against her religious beliefs).
 * Mary's waters broke for Sheldon and Missy in a K-Mart.
 * Sheldon was raised in a Christian household in Galveston, East Texas, Texas, USA (Texas just happens to be the same state that Jim Parsons was actually born in), although he once his mom had to help his dad during tornado season, as the aluminum house he had slipped off its cinder blocks. (This could have been his father's way of a tornado shelter or his parents divorced by then and he moved into an aluminum trailer. The reason for these explanations being as we saw Sheldon's childhood home in the season 3 premier, where his mother still lives.)
 * Sheldon has perfected "glow-in-the-dark Fish"
 * Sheldon has 212 friends on MySpace.
 * Sheldon is allergic to bees and cats and gets asthma when he is around them (despite having a pet cat as a child and a whole glaring of cats when he missed Amy.)
 * Sheldon considers himself to be the first "Homo novus" - a new, evolved species of homo sapiens.
 * Sheldon doesn't believe in luck or coincidence, instead citing the Law of Large Numbers (LLN) in statistics as the explanation for such phenomena.
 * Sheldon was humiliated on National Radio during NPR's Science Friday with Ira Flatow when his voice became extremely high pitched due to Helium seeping into his office as part of a prank by Barry Kripke.
 * Sheldon agrees with the theory that 75-80% of any Rock-Paper-Scissors games you play with a person you are familiar with end up in a tie, and accordingly he prefers the variation Rock-Paper-Scissors-Lizard-Spock.
 * Sheldon used a Doppler Effect costume for Halloween.
 * Sheldon uses his Green Lantern action figure as a safe place for his emergency money.
 * Sheldon is fluent in Morse code.
 * Sheldon's favorite amino acid is Lysine.
 * Sheldon thinks that his very strong attention to hygiene and his skill in writing Java Applets are the main reasons why his friends like him.
 * Sheldon loves trains and monkeys.
 * Sheldon fears birds and (according to Raj) dogs.
 * Sheldon had a cat named Lucky when he was a child, and this cat died because it was hit by a car. According to Leonard, this is another example of Sheldon's inability to understand irony.
 * Sheldon learned how to swim (on the floor) online.
 * Sheldon hates people who hiss at home.
 * Sheldon cannot stand whistling.
 * Sheldon thought about creating a Griffin when he was a child, after the family cat died. But his parents didn't want to secure the appropriate Eagle eggs and Lion semen.
 * Sheldon was very busy in his teenage years examining the range of diffusion in the supersymmetric theories, which brought him to re-examine the ultraviolet properties of supergravity a loop.
 * Sheldon's expenses account for 46.9% of his after-tax income.
 * Sheldon imposes and teaches behavior lessons to any friend of his who disappoints him for 3 consecutive times.
 * Sheldon thrives off his work, and if left jobless he loses all focus and moves onto a new experiment/obsession every day, much to Leonard's dismay.
 * Sheldon does not like teddy bears because he thinks bears are terrifying.
 * Sheldon was called by Leonard "one lab accident away from becoming a super villain".
 * Sheldon loves having his brain scanned.
 * Sheldon hates when people pronounce the "t" in often.
 * Sheldon only shows genuine affection for one person, his grandmother (or Meemaw), whom he writes to.
 * Sheldon is a Taurus placing his birthday between 20 April and 21 May.
 * Sheldon, though unwilling to fight, is physically the strongest of the group, easily holding his own against Raj in an arm wrestle, and once referred to Leonard and Howard as 'tiny tiny men'.
 * Sheldon's little toes and lateral incisors are degenerated, which he says is due to his high level of evolution which keeps him from using a motor vehicle.
 * Sheldon once got chased up the elm tree at the front of his house by his neighbour's chicken.
 * Sheldon once took a bet with Howard about a species of cricket, but lost and had to give Howard his Flash comic book.
 * Sheldon went to a Science Fiction convention on a bus for 10 hours and violated his personal rule of not urinating on buses twice to see Wil Wheaton, who didn't show up at the convention. This and the events of the tournament and bowling alley, led Sheldon to consider Wheaton his arch nemesis. He has made three websites dedicated to hating him: wilwheatonstinks.com, .org and .net.
 * Sheldon has actually been kind to Penny; in two episodes he actually drove her to the hospital because she dislocated her shoulder, and loaned her a significant amount of money to help her in a financial pinch. (Even though this led Penny to think everyone was drilling her on her financial situation, even when they weren't.)
 * Sheldon was once offered a position at a secret military base, but was later forced to deny the position due to his inability to keep secrets.
 * Sheldon thought that the trip he and his friends took to the North Pole in Season 2/3 was "a hoot and a half."
 * It was mentioned that Sheldon and Leonard once had (before they were robbed) "A TV, 2 laptops, 4 external hard drives, a PS2, PS3, Xbox, Xbox 360, a classic Nintendo, a Super Nintendo, a Nintendo 64, a Nintendo Wii, Halo 1-3, Call of Duty 1-3, Rock Band 1-2, Final Fantasy 1-9, Legend of Zelda, Legend of Zelda: Ocarina of Time, Legend of Zelda: Twilight Princess, Super Mario Bros., Super Mario Galaxy, Mario and Sonic at the Winter Olympics, and Ms. Pac-Man. They then probably got all the games and consoles again with a new T.V. and new computers. Sheldon's new computer came with Windows 7 which he doesn't like because it's much more user friendly than Windows Vista.
 * Sheldon has adhesive whimsical duck stickers, holding umbrellas in his bathtub to prevent slipping.
 * Sheldon keeps a daily log of social interactions called Sheldon's Log ( in place of Captain's Log)
 * Sheldon doesn't trust banks because he believes that ATM machines will lead the charge of the robot armies when they revolt against humans.
 * Sheldon keeps Band-Aids with him at all times, as well as in his kitchen, top desk drawer, etc.
 * As of The Excelsior Acquisition, Sheldon has a restraining order from Stan Lee as well as Leonard Nimoy.
 * Sheldon has an in depth knowledge of American Football, since he was raised in Texas and his father would force him to watch it from the time he was four until he went off to college—the longest 7 years of Sheldon's life.
 * Sheldon rarely laughs, but when he does, it is a quick internal breath whilst showing a small smile.
 * Sheldon has never worn a shirt with words, unless a shirt logo has words on it, like in episode 5 of season 4, and always wears a long sleeved shirt under a t-shirt
 * Sheldon got drunk two times during the series: at the end of The Grasshopper Experiment and in The Pants Alternative and in the last he showed a sense of humour and irony above what he normally has.
 * Sheldon apparently believes in the possibility of time travel to the past according to the beginning of The Luminous Fish Effect, explanations of time paradoxes in The Nerdvana Annihilation and a point of the room-mate agreement in The Staircase Implementation.
 * When somebody is distressed, Sheldon consoles them by saying "There, there"- only proof of his compassion towards other fellow human beings.
 * Sheldon is scared of waking Penny before 11 am. Because she has a "I'll punch you in the throat" rule if he does.
 * Sheldon is skilled in weaving as he is seen weaving ponchos in his apartment.
 * If nothing is approved by Sheldon, he will not go through with it. (This is seen when Leonard, Raj, Howard, and Sheldon are trying to figure out the best way to see a movie. With Sheldon not approving any ideas, the rest leave him and he responds: "They're right. That was the only way.")
 * Prevening - Sheldon's made up word for the hours too late for Afternoon, but too early for evening.
 * Leonard had to surpass 3 barriers set by Sheldon in order to live with him.
 * Sheldon prefers the word "Hookum" to Bogus, Hocus Pocus, Mumbo Jumbo and Hokie Pokie.
 * He considers Amy Farrah Fowler a friend who is a girl, but not his girlfriend.
 * He missed getting Stan Lee to autograph his comic since he had to go to traffic court to pay a fine, but ended up in jail after he insulted the judge and refused to apologise. He then went to his house with Penny and ended up with a restraining order against him.
 * Sheldon had built a robot called Shelbot, but was eventually discarded since Penny and Leonard were quite annoyed at Sheldon's idea for doing so.
 * Sheldon owns a Flash costume which he, so far, has worn on three occasions: in The Middle Earth Paradigm before Penny's Halloween party before switching to a Doppler Effect patterned suit, in The Work Song Nanocluster when high on caffeine and in The Justice League Recombination when attending a New Year's Eve costume party.
 * Prior to Sheldon's date with Amy in The Robotic Manipulation, the closest he had ever come to a such was "a semi-incestuous Teens for Jesus Fourth of July Hoedown" at which he square-danced with his twin sister, Missy.
 * Sheldon once attempted to declare his and Leonard's apartment a sovereign state and even made some currency for it. This was around the time Sheldon got fired from the university and he kept changing obsessions.
 * Sheldon hates dirty socks. This is demonstrated by the time that Leonard, Raj, and Howard signed Sheldon up on a dating site and the site found Sheldon's perfect match, but Sheldon refused to go until Raj told him that he put a dirty sock in his apartment and would not remove it unless Sheldon went on the date.
 * According to Sheldon in a deleted scene/blooper in "The Maternal Capacitance", the last time his mother visited, she tried to trick him into getting re-baptized below the Santa Monica Pier.
 * Sheldon went to Johnson Elementary School until he went to college at age 11. It was there he earned the nickname, "Smelly Pooper" with kids going around saying, "Shelly Cooper is a Smelly Pooper". Amy Farrah Fowler believes this is gold for gossip.
 * When Sheldon was under Howard's Mom's valium, he revealed that his mother used to smoke in the car. While Jesus said it was OK, they couldn't tell their dad, George.
 * Due to his good archery skills taught by his father George, Sheldon believes he would have made a great elf.
 * There are two pieces of tape on the floor in Leonard and Sheldon's bathroom. One is in front of the sink and people must brush and floss their teeth from behind this piece of tape. A second piece is in front of the toilet for those that stand up to pee, though what exactly it marks was not specified. If someone gets the mirror or floor dirty, before Sheldon's inspection, they can lose their T.V. privileges.
 * As part of the roommate agreement created by Sheldon, Leonard has to wash his feet in a special tub before he gets in the bath or shower.
 * According to him, the best number is 73, stating that 73 is the 21st prime number and its mirror, 37, is the 12th prime number. And 12's mirror, 21, is the product of 7 and 3. It is also a palindromic binary number 1001001.
 * He once had to give artificial respiration in a bus when elderly nun passed out from sunstroke.
 * Sheldon, alongside Leonard, Howard and Raj are only characters who appear in every episode.
 * He is excellent at dancing waltz, rumba and cha-cha.
 * Mrs. Wolowitz refers to him as "that skinny weirdo".
 * He has never had a girlfriend until Amy Farrah Fowler, and even then, he still denies it.
 * Sheldon wears socks in bed.
 * Sheldon does not like Director Joel Schumacher as he "nearly destroyed the Batman movie franchise"
 * Sheldon can speak Finnish.
 * He's not insane, his mother had him tested.
 * He is following steps of Captain Kirk, Captain Crunch and Captain Kangaroo.
 * Sheldon doesn't like Geologists and refers to them as "The Dirt People"
 * In the un-aired pilot, Sheldon admits that he is physically aroused by large female butts, but attributes it to the evolutionary trait of seeking women by how well they would bare children.
 * Sheldon doesn't like the Harp because he thinks he will experience an episode from his past, as the instrument was always used in classic TV sitcoms.
 * He has 61 mortal enemies.
 * Wil Wheaton is now his friend and Brent Spiner is his mortal enemy which is opposite of the first.
 * Sheldon recently became a notary public.
 * Every Monday, Sheldon eats oatmeal, and every Friday, Sheldon eats french toast.