Leonard: Buddy, I know me moving in with Penny feels like a big change, but it's not.
Sheldon: How can you say that? Amy's gone, and you two are married now, so it's only a matter of time before you're gone, too.
Penny: Okay, you don't know what's gonna happen.
Sheldon: No, I do. Eventually you'll want more space and you'll move into a house. And then instead of dinner a couple of times a week, it'll only be a couple of times a month. And then it'll only be on special occasions, like when Bernadette divorces Wolowitz.
Or-or-or like when Koothrappali's weird girlfriend admits where she buried his body.
Or Amy's wedding, where she's marrying someone better than me.

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.

Howard: You know what's really happening here? Your girlfriend is breaking up our band.
Raj: She has nothing to do with this. I am my own man.
Howard: Oh, please. Your brain belongs to whoever's willing to sleep with you.
Raj: That is so not true.
Howard: Really? Remember when you were gonna get circumcised for Rachel Bernstein?
Raj: That had nothing to do with Rachel. It was an overreaction to a bad zipper injury.

Howard: What kind of music are you thinking of?
Stuart: I like all kinds of music, but my favorite genre is free.

Howard: I don't need this. I'm quitting the band!
Raj: Fine, I quit, too!
Howard: Then get out of my house!
Raj: With pleasure!
*door slams*
*Howard sighs*
Howard: Raj, wait!
Raj: What took you so long?