Sheldon: Thankfully all the things my girlfriend used to do can be taken care of with my right hand.

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.

Sheldon: Hello.
Leonard: Hey, buddy, can we have some privacy?
Sheldon: Of course. Wouldn't want to intrude. (takes red bra out of his pocket and hands it to Penny) This is yours.
Penny: Okay, when I'm done with him, I'm gonna need more information.
Sheldon: Nothing odd. I just wanted to rub Amy's nose in it.

Leonard: I'm not being weird. Am I being weird?
Sheldon: Yes. And that's coming from me.

Amy: I've seen and talked to you more in the two days we've been broken up than in the last two months we were together.
Sheldon: Well, if you want to see less of me, maybe we should go out again.