Mrs. Wolowitz: Howard! What are you doing in there?
Howard: I'm taking a bath.
Mrs. Wolowitz: I hope that's all you're doing, we share that tub.
Howard: Don't remind me.

Howard: You know, I'm really glad you decided to learn Mandarin.
Sheldon: Why?
Howard: Once you're fluent, you'll have a billion more people to annoy instead of me.

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

Sheldon: Sheldon Cooper does not cry.
Howard: That's true, you'd rust.

Barry Kripke: Hey, Cooper. I hear you're going to be on the radio with Ira Flatow from Science Friday next week.
Sheldon: Thank you, Kripke, for depriving me of the opportunity to share my news with my friends.
Barry Kripke: My pleasure.
Sheldon: My thanks were not sincere.
Barry Kripke: Ah, but my pleasure is.

Sheldon: What are you talking about?
Leonard: The cultural paradigm in which people have sex after 3 dates.
Sheldon: I see. Now, are we talking date the social interaction or date the dried fruit?

Sheldon: Biologically speaking, Howard is perfectly justified in seeking out the optimum mate for the propagation of his genetic line. Howard: Thank you, Sheldon. Sheldon: And whether that propagation is in the interest of humanity is, of course, an entirely different question.