Sheldon: In Papua New Guinea, there's a tribe when a hunter flaunts his success to the rest of the village, they kill him and drive away evil spirits with a drum made of his skin. Superstitious nonsense, of course, but one can see their point.

Sheldon: Are you upset about something?
Leonard: What was your first clue?
Sheldon: Well, it was a number of things. First, the late hour, then you demeanor seems very low energy, plus your irritability.
Leonard: Yes, I'm upset!
Sheldon: Oh. I don't usually pick up on those things. Good for me.
Leonard: Yeah, good for you.
Sheldon: (walks away and then turns back) Oh, wait. Did you want to talk about what's bothering you?
Leonard: I don't know. Maybe.
Sheldon: Wow! I'm on fire tonight.

Leonard: I know what you're doing.
Sheldon: You do?
Leonard: You're using chocolate as a positive reinforcement for what you consider is a correct behavior!
Sheldon: Very good. Chocolate?

Sheldon: Is my hamburger medium-well?
Leonard: Yes.
Sheldon: Dill slices not sweet?
Leonard: Yes.
Sheldon: Individual relish packets?
Leonard: Yes.
Sheldon: Onion rings?
Leonard: Yes.
Sheldon: Extra-breading?
Leonard: I asked.
Sheldon: What did they say?
Leonard: No.
Sheldon: Did you protest?
Leonard: Yes.
Sheldon: Vociferously?
Leonard: No.
Sheldon: Well then what took you so long?

Amy's Mom: It's nice to meet you too Sheldon, I honestly didn't believe Amy when she told me she had a boyfriend.
Sheldon: I assure you, I am quite real and I'm having regular intercourse with your daughter.
Amy's Mom: What?
Sheldon: Oh yes, We're like wild animals in heat. It's a wonder neither of us has been hurt!
Amy's Mom: Amy? What is he saying?
Amy: You wanted me to have a boyfriend, mother, well here he is! Have to sign off now. My hunger for Sheldon is stirring in my loins.
Sheldon: Oh yes. It's time for me to make love to your daughter's vagina.

Penny: Now, honey, it's okay. You don't have to get me anything in return.
Sheldon: Of course I do. The essence of the custom is that I now have to go out and purchase for you a gift of commensurate value and representing the same perceived level of friendship as that represented by the gift you've given me. It's no wonder suicide rates skyrocket this time of year.
Penny: Okay, you know what? Forget it. I'm not giving you a present.
Sheldon: No, it's too late. I see it. That elf sticker says to Sheldon. The die has been cast, the moving finger has writ, Hannibal has crossed the Alps.

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 I'm a clown made of candy. But I don't dance.

Amy: Are you in the lanthanide series?
Sheldon: Amy, it's Penny's turn. Penny.
Penny: Uh, I dunno. Are you food?
Sheldon: That's not a apropos! We've already established I'm found on the Periodic Table.
Penny: Well, it's a table, right? I mean, why can't there be food on it?
Sheldon: I knew she wasn't lead car material.

Sheldon: Interesting. Sex works even better than chocolate to modify behavior. I wonder if anyone else has stumbled onto that.

Sheldon: Penny.
Penny: Yeah.
Sheldon: Thanks for letting me stay here.
Penny: Oh, you're welcome sweetie.
Sheldon: Okay, I'm sleepy now get out.

Penny: Honey, have you ever run before?
Sheldon: Certainly. I've run from bullies, dogs, angry chickens and one particularly persistent PE teacher determined to bend me over and give me a scoliosis test.

Sheldon: She calls me moon-pie because I'm nummy-nummy and she could just eat me up.

Sheldon: We no longer live at 2311 Los Robles. We live at 311 Los Robles. [holds up number 2 fixture]
Leonard: You changed the address on the building? What about mail?
Sheldon: No worries. I explained our predicament to our letter carrier. He was sympathetic. His exact words were, "Got your back, Jack. Bitches be crazy."

Penny: OK Sheldon, what can I get ya?
Sheldon: Alcohol.
Penny: Could you be a little more specific?
Sheldon: Ethyl alcohol, 40 millilitres.

Store Clerk: Excuse me, Sir, you don't work here.
Sheldon: Yes, well apparently neither does anyone else.