Leonard: Will you stay out of this?
Sheldon: If only Penny had said that once in a while.

Sheldon: I miss Stuart's place. All this loud music and exposed brick, is this a comic book store or a rave at the third little pig's house?

Howard: All I know is he's got my mother buying four ply toilet paper. Four ply! If his butt is so delicate, why doesn't he use an Angora rabbit?
Sheldon: For starters, they shed and bite.

Emily: I'm a resident at Huntington Hospital.
Sheldon: Oh, I like their emergency room. You know, even if it turns out you don't have Dengue Fever, they still let you take a lollipop.

Howard: Since when do you read social science?
Sheldon: I go to the bathroom like everybody else.

Leonard: You didn't lose anyone when you met Amy.
Sheldon: The study refers to romantic partners. That's not the way I would categorize the two of us.

Amy: It would make me so happy if you said things like that.
Sheldon: We got an 8.2. Trust me, you're happy.

Raj: You suck, Wolowitz!
Sheldon: He makes a valid point!

Leonard: I've seen you guys ignore each other for hours, doing totally different things.
Sheldon: It's called parallel play.
Leonard: Yeah, toddlers do that.
Sheldon: Not as well as we do.

Sheldon: If you've got a problem basing a relationship on a contract, I'd like to tell you about thirteen plucky colonies that entered a relationship agreement called the U.S. constitution. And it may not be cool to say so, but I think that love affair's still pretty hot today.

Raj: You suck, Wolowitz!
Howard: What's that about?
Raj: I'm heckling you. It's a beloved part of baseball.
Sheldon: He's right. And given that you're probably still waiting to be picked for a game that was played in fifth grade, I'm sure you do suck.

Sheldon: Can't talk. Spit ball. Probably gonna die.

Leonard: Sheldon, I promise, your uvula does not have an STD.
Sheldon: Are you sure? It just doesn't feel as innocent as it used to.

Howard: You reported me to human resources?
Sheldon: You violated the sanctity of my mouth.

Raj: Oh, you bought cookies?
Sheldon: Yes, fig newtons. I was going to ask which scientist both helped to discover calculus and had a famous cookie named after him. And then after someone said Newton, I was going to tell them they're wrong. The cookies are named after a town in Massachusetts. And then I'd throw the cookies away.