Leonard: I would pull this car over and kick you out, but if Penny dumps me, you're all I got.

Althea: Now I see three of you. Do we know the father, or is this some Mamma Mia nonsense?

Sheldon: I knew we should've never mentioned us living together in the first place.
Amy: She was gonna find out eventually.
Sheldon: Disagree. We've known about evolution since 1859. She still believes in Noah and his amazing zoo boat.

Bernadette: What's so funny?
Howard: Raj is looking for a cheap place to live, and I wrote "India."
Bernadette: Don't post that; be supportive.
Howard: Maybe you should be supportive of my hilarious jokes.

Penny: Do they know why the pipes burst?
Amy: They didn't say.
Leonard: Buildings that have a combination of copper and galvanized steel are susceptible to pinholes and corrosion caused by the mobility of ions in the water. Can't have your head shoved in a toilet as much as I did and not pick up a few things about plumbing.

Sheldon: Stuart, wait. I do know what it feels like to be left out.
Bert: I know how it feels, too.
Sheldon: All right, this is about me and him; you're not part of it.

Amy: Sheldon, your mother's an attractive woman. You need to get used to the fact that men are going to be interest in her.
Sheldon: Well, and you need to drive the car and mind your business.
Amy: I will not have you be disrespectful to me.
Sheldon: What- you're not my mother.
Mary Cooper: Don't you be disrespectful to her.
Sheldon: Yes ma'am.
Mary Cooper: You'll get there. You've just gotta put some zing on it.

Sheldon: We seem to be moving on to the annual coitus portion of your birthday festivities.
Amy: Is that okay?
Sheldon: I didn't put on my come-hither plaid PJs for nothing.

Raj: What's the worst that could come of this meeting?
Howard: I don't know. They take the invention away, and I get nothing?
Raj: Okay, that's not so bad. You know what happened to the scientists that worked on the Manhattan Project? The government forced them to move to the desert. They had to live in secret, and when Oppenheimer objected to what they made him do, they destroyed his reputation.
Howard: What's the point of that story?
Raj: I just read a book about Oppenheimer, seemed like a chance to show off.

Bernadette: Apple slices? What kind of lunatic goes to McDonald's and gets fruit?

Leonard: Sheldon, this is not a big deal. It's a little white lie, everyone does it.
Raj: Not me, I'm a 100% honest in all of my relationships.
Howard: And how single are you right now?
Raj: Eating-cake-on-the-toilet single.

Sheldon: Being with Amy has awoken the sexual creature within. When I see a pretty gal walking down the street, I think, "hubba hubba" like any other guy.
Penny: You kiss your mother with that mouth? 'Cause it's fine.

Amy: All right, you can open your eyes. I thought I'd let Harry Potter make things hotter.

Penny: You know, when Leonard's feeling anxious, I make him take a long walk.
Amy: Does that help?
Penny: For a while, then he comes back.

Sheldon: I admire you, Leonard.
Leonard: Really, why?
Sheldon: You're happy with who you are. You don't get jealous of other people. Instead of being weighed down by ambition, you just float along like a dead body in a river.
Leonard: I couldn't just take the compliment. I had to ask why.