Sheldon: Are you bothered that I can so easily manipulate you?
Howard: Don't push me, Sheldon. I may be small, but I took kung fu when I was 13, and I remember a good deal of it.
Sheldon: Oh, really? Well, I grew up with an older brother and a very contentious twin sister and I believe I could easily best you in any physical confrontation, be it noogies, swirlies or the classic why are you hitting yourself?

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.

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.

Wolowitz: I think that you and Penny had a poor night.
Leonard: It wasn't poor. It was ... just fine.
Raj: Dude, the fourth Harry Potter movie was just fine.

Raj: Ooo, big talk from a man who was once treed by a chicken.