Sheldon: I will play the word "at" for two measly points, throwing the game and thus securing my friendship with the smartest man in the world.
Howard: What are you waiting for? Hit send.
Sheldon: I can't. Losing on purpose is intellectually dishonest.
Raj: So don't do it.
Sheldon: Oh, but I want to be Hawking's friend.
Howard: So do it.
Sheldon: Oh, but if I do, I'll be a phony, a sellout, a Hollywood poser.
Raj: Then don't do it.
Sheldon: I won't. This feels right. My mother always said, to thine own self be true.
Howard: Good for you.
Sheldon: 'course she also told me that every animal in the world got on one boat, so what does she know? And send.

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.

Leonard: I did a bad thing.
Sheldon: Does it affect me?
Leonard: No.
Sheldon: Then suffer in silence.

Stephen Hawking: What does Sheldon Cooper and a black hole have in common? They both suck.

Sheldon: Steven Hawking's a genius and he talks like a robot. It's everything I ever wanted in a friend.