Sheldon: I thought that subject had run its course, so I changed it. It's called reading the room, Amy.

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.

Bernadette: Maybe we should get one of those machines to help her up the stairs.
Howard: You mean a forklift?

Bernadette: I'm glad I got that mocha. And you know what else I'm glad about? I bought you a brownie and I ate it in the car!

Penny: I finally realize I don't need to be famous or have some big career to be happy.
Leonard: Well what do you need?
Penny: You, you stupid Poptart.