Sheldon: No, Mother, I could not feel your church group praying for my safety. The fact that I'm home safe does not prove that it worked. That logic is post hoc, ergo propter hoc. [lowers his voice] No, I'm not sassing you in Eskimo talk.

Sheldon: Oh Lord, they re-did the menu.
Leonard: So what, it's the same food.
Sheldon: Really? Look at this: General Tso's chicken is no longer under specialties. It's now under chicken.
Raj: So?
Sheldon: Yes General Tso.
Raj: Not Tso the chicken, so the question. So?
Sheldon: So? Did the chef loose confidence in himself or the dish. And just look at this, Shrimp with mobster sauce. What is mobster sauce?
Leonard: It's obviously a typo.
Sheldon: Perhaps. Or perhaps this restaurant is now a front for organized crime. For all we know the mobster sauce actually contains chunks of deceased mobsters.
Raj: No, I just think it means it's the kind of sauce mobsters like.
Howard: It doesn't mean anything, it's just a typo!
Leonard: Here's an idea: why don't we go out for pizza?
Sheldon: Good idea. We'll go to Corleone's.
Howard: Sure, no mobsters there.
...
Sheldon: The more I think of it, mobster sauce couldn't possibly contain actual mobsters.
Leonard: [impatient] Why not?
Sheldon: It's listed under seafood.

Sheldon: Penny, while I subscribe to the "Many Worlds" theory which posits the existence of an infinite number of Sheldons in an infinite number of universes, I assure you that in none of them am I dancing.
Penny: Are you fun in any of them?
Sheldon: The math would suggest that in a few of them I'm a clown made of candy, but I don't dance.

Sheldon: Thanks for seeing me on such short notice.
Leonard: What do you want?
Sheldon: Maybe this isn't a good time.
Leonard: Tell me what you want or I swear to God I will kill you.
Sheldon: Do you really think death threats are a good way to start this conversation?
Leonard: Alright I'm sorry.
Sheldon: Sometimes your lack of social skills astonishes me.
Leonard: What do you want?
Sheldon: You may wanna sit down.
Leonard: I'm in bed!
Sheldon: Point taken. You may wanna sit up.
Leonard: Just tell me what you want!
Sheldon: I've been seeing Penny behind your back.
Leonard: When you saying seeing Penny, what do you mean?
Sheldon: We had dinner last night. She made me spaghetti with little hot dogs. I like spaghetti with little hot dogs.Well a hot dog. I gave up the other 5 hot dogs to a real dog. A real big dog. A hell hound. There'll be a tangent line at the end, it's not important.
Leonard: Then why did you have Chinese food with us?
Sheldon: Wolowitz made it very clear who's side I should be on. Clearly the male comrade comes before the woman who will sell her body for money.
Leonard: Is it possible that he said bros before hoes?
Sheldon: Yes, but I rephrased to avoid offending the hoes.
Leonard: Sheldon, I don't care if you wanna be friends with Penny.
Sheldon: Really?
Leonard: Yeah.
Sheldon: You mean all the emotional distress I've been feeling is essentially useless and in vain.
Leonard: I guess so.
Sheldon: Well as my Meemaw would say, Looks like we butchered a pig but nobody wanted bacon. Oh and as for the tangent line. Sheldon and the hell hound. OR How I lost my hot dogs.

Sheldon: The 'Check Engine' light is on; we need to find a service station.
Penny: No, the light's been on since I bought the car.
Sheldon: All the more reason to consult with a mechanic before it explodes!
Penny: It's not gonna explode, just keep driving. Warp speed ahead, Mr. Spock.
Sheldon: Mr. Spock did not pilot the Enterprise, he was a science officer, and I guarantee you that if he ever saw the Enterprise's 'Check Engine' light blinking, he would pull the ship over immediately!

Sheldon: Waterfalls!
Raj: What?
Sheldon: Waterfalls, crashing waves, babbling brooks.
Howard: What are you doing?
Sheldon: Subliminal messaging. I'm going to make you want to pee. Dripping faucets, leaky gutter, peeing.
Raj: It's not working, dude.
Sheldon: Oh it's working alright. I have to pee.
Raj: Then let go of the ring and go.
Howard: Well actually I wouldn't mind going either.
Raj: Well on the count of three. 1, 2...
Sheldon: Wait, just to be clear. When we get to three, do we stand up? Or do we pee?
Howard: We stand up.
Sheldon: Excellent choice.
Raj: 3.
Howard: Something tells me this was a bad day to wear suede shoes.

Sheldon: What are they doing here?
Leonard: We came to apologize again and bring you home. So why don't you pack up your stuff, and we'll head back?
Sheldon: No, this is my home now. Thanks to you, my career is over, and I will spend the rest of my life here in Texas trying to teach evolution to creationists.
Mrs. Cooper: You watch your mouth, Shelly. Everyone's entitled to their opinion.
Sheldon: Evolution isn't an opinion, it's fact.
Mrs. Cooper: And that is your opinion.
Sheldon: [to the guys] I forgive you, let's go home.
[Sheldon leaves to pack]
Mrs. Cooper: [smiling] Don't tell me prayer doesn't work.

Sheldon: Why are you crying?
Penny: Because I'm stupid.
Sheldon: Well, that's no reason to cry. One cries because one is sad. For example, I cry because others are stupid, and that makes me sad.

Stuart: You guys still on for bowling tonight?
Sheldon: Oh yes. In fact, I've prepared some trash-talk for the occasion. Ahem...You bowl like your momma! [short pause] Unless she bowls well, in which case you bowl nothing like her.
Stuart: Oh...Ouch.
Sheldon: That is what is referred to as a burn on you.

Zack: Wow, is that the laser? It's bitchin'.
Sheldon: [sarcastically] Yes. In 1917 when Albert Einstein established the theoretic foundation for the laser in his paper "Quantentheorie der Strahlung", his fondest hope was that the resultant device be "bitchin'".
Zack: Well, mission accomplished.
[Sheldon looks at him in suprise and confusion]

[After the guys hear a cricket and Sheldon says its a snowy tree cricket based on the chirps]
Howard: I am willing to bet anything, that's an ordinary field cricket.
Sheldon: I can't take your money.
Howard: What's the matter? You chicken?
Sheldon: I've always found that an inappropriate slur. Chickens are not, by nature, at all timid. In fact, when I was young, my neighbor's chicken got loose and chased me up the big elm tree in front of our house.
Raj: Chickens can't climb trees.
Sheldon: Thank God.

[After their apartment has been robbed]
Leonard: What are we supposed to do now?
Sheldon: The only thing we can do. Watch TV on our phones until the criminals return and bludgeon us to death in our sleep.

[at the site for Sheldon's online date]
Amy: Excuse me. I'm Amy Farrah Fowler, you're Sheldon Cooper.
Sheldon: Hello, Amy Farrah Fowler. I'm sorry to inform you that you've been taken in by unsupportable mathematics designed to prey upon the gullible and the lonely. Additionally, I am being blackmailed with a hidden dirty sock.
Amy: If that was slang, I'm unfamiliar with it. If it was literal, I share your aversion to soiled hosiery. In any case, I'm here because my mother and I have agreed that I will date at least once a year.
Sheldon: Interesting. My mother and I have the same agreement about church.
Amy: I don't object to the concept of a deity, but I'm baffled by the notion of one that takes attendance.
Sheldon: Well, then you might want to avoid East Texas.
Amy: Noted. Now, before this goes any further, you should know that all forms of physical contact up to and including coitus are off the table.
Sheldon: May I buy you a beverage?
Amy: Tepid water, please.
Howard: [to Raj, seeing their "experiment"] Good God, what have we done?
Season 4

[Howard and Raj are fighting. Eventually, Sheldon loses his cool]
Sheldon: Stop it both of you! All this fighting, I might as well be back with my parents! "Damn it, George, I told you if you didn't quit drinkin', I'd leave you!" "Well, I guess that makes you a liar, 'cause I'm drunk as hell and you're still here!" "Stop yelling! You're making Sheldon cry!" "I'll tell you what's making Sheldon cry! That I let you name him Sheldon!" [Sheldon storms out]
Howard: Boy, what got him so upset?
Raj: Oh, sure, you can tell when Sheldon's upset.

[Howard's phone rings]
Howard: Damn, it's my mother.
Bernadette: Are you going answer it?
Howard: I'm torn. She might be dying. I wouldn't want to miss that. On the other hand, if I let it go to voicemail, I could play it over and over.
Bernadette: I know how you feel. My mother makes me crazy.
Howard: Not as crazy as my mother makes me.
Bernadette: Oh, yeah, does your mother call you every day at work to see if you've had a healthy lunch?
Howard: My mother calls me at work to see if I had a healthy bowel movement.
Bernadette: Okay, well, does she lay out your clothes for you in the morning like you're 9 years old?
Howard: You live with your mother?
Bernadette: No. That's the sad part.
Howard: Okay, check this out: my mother made me wear rubber gloves to kindergarten so I wouldn't pick up a disease from the other children.
Bernadette: That's nothing! I couldn't ride a bicycle because my mother was afraid I'd hit a bump and lose my virginity.
Howard: Oh, wow. You didn't, did you?
Bernadette: Not on a bicycle. In a Camry. [short pause]
Howard: Corolla! More wine?
Bernadette: I'd love some!
Howard: Listen, you have to come to Shabbat dinner at my house sometime.
Bernadette: Why?
Howard: Well, a Catholic girl like you, wearing a big cross like that, might just give my mother the big brain aneurysm I've been hoping for.
Bernadette: Okay. But only if you come to Sunday dinner at my house wearing a yarmulke.
Howard: It's a date.
Penny: [aside to Leonard] Am I a matchmaker or what?