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

Raj: I don't like bugs, okay. They freak me out.
Sheldon: Interesting. You're afraid of insects and women. Ladybugs must render you catatonic.

Sheldon: Scissors cuts paper, paper covers rock, rock crushes lizard, lizard poisons Spock, Spock smashes scissors, scissors decapitates lizard, lizard eats paper, paper disproves Spock, Spock vaporizes rock, and as it always has, rock crushes scissors.

Sheldon: Why are you crying?
Penny: Because I'm stupid.
Sheldon: 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.

Howard: Try telling him it's a non-optional social convention.
Penny: What?
Howard: Just do it!
Penny: It's a non-optional social convention.
Sheldon: Oh, fair enough.
Howard: He came with a manual.

Sheldon: What computer do you have? And please don't say a white one.

Howard: Okay, I get it. I know how the world works. How about if I were to introduce you to the man who freed your people.
Nurse: Unless my people were freed by Benjamin Franklin and his five twin brothers, you are wasting your time.