Penny: It's like if you're dating someone you're not that into and then they break up with you. Then you want them more than ever.
Sheldon: I have no idea what she's talking about, but we're ganging up on you so I agree.

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: No, that's okay. I can fight my own battles. Isn't that right, Bawwy?
Barry Kripke: Is that a reference to my speech impediment? That's pretty hurtful. I can't control it.
Sheldon: You're right. That was uncalled for. I take it back.
Barry Kripke: Of course you do, because you're The Retractor!

Bernadette: Aww, Raj did the dishes.
Howard: How do you know I didn't do them?
Bernadette: Because once when all the knives were dirty, you cut a bagel with your keys.

Penny: (To Raj's dog) Bark once if you need me to call PETA.