Howard: "Article three: As it pertains to this project, Dr. Sheldon Cooper promises to abstain from all insulting or disrespectful language directed toward Howard Wolowitz, including but not limited to: mockery of engineering, his height, his hair, his wardrobe, and his insane belief that the Ghost Rider movie was, quote, 'not that bad'."

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.

Howard: So you can never take it (the sweater) off?
Leonard: No.
Raj: Not even to sleep?
Leonard: No.
Howard: So you're just an idiot?
Leonard: It's called proving a point.
Howard: Is the point you're an idiot?

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

Leonard: Hang on. Maybe there should be a "no insult" clause about me, too.
Sheldon: Do you still like cilantro?
Leonard: Yeah.
Sheldon: You're tying my hands here.

Howard: See, he's not wearing a tie.
Leonard: Well, he's a patent attorney. Maybe his tie is pending.

Leonard: Hold on, hold on. So the three of us do all the work and only end up with 25%? Patent Attorney: Dr. Hofstadter, this university has been paying your salaries for over ten years. Did you think we do that out of the goodness of our hearts?
Leonard: Well, until you just said that mean thing, kinda.