Sheldon: Eat one of your Luna bars. Very often when women think they're angry, they're really just hungry.

Sheldon: You may not realize it, but I have difficulty navigating certain aspects of daily life. You know, understanding sarcasm, feigning interest in others, not talking about trains as much as I want. It's exhausting!

Sheldon: (Playing hackey sack) One, two, three, four, five, six, seven, eight. Drat. I'm never going to get to forty-three again. One, two, three, four. Rats.

Dimitri: What are you gonna do when you get back to Earth?
Wolowitz: Oh, I'm never going back.

Sheldon: Leonard, the transformers teach us that things are not always what they appear to be. You know, like, a semi truck might be an alien robot, or someone in a romantic relationship might feel differently than they appear to.

Sheldon: Ooh, now that is a treat that's hard to beat. Get the Mad Hatter on the horn. I'm having a tea party!

Sheldon: *knock knock knock* Wil Wheaton!
*knock knock knock* Wil Wheaton!
Wait, how many was that?

Howard: Okay, here it is. Bernadette said you guys are all sick of me talking about my trip to space. Is that true?
Sheldon: Yes.
Raj: No.
Sheldon: We seem to have different approaches here. I was going for helpful honesty. I have no idea what you're doing.
Raj: It's called being nice.
Sheldon: Okay. If you think being nice will get him to shut up, I'll try it.

Sheldon: Excuse me. This is not about protecting my friend. Im a big fan of homeostasis. Do you know what that is?
Penny: Of course not.
Sheldon: Homeostasis refers to a systems ability to regulate its internal environment and maintain a constant condition of properties like temperature or pH.
Penny: Worst bedtime story ever!

Leonard: Please be good, please be good. Uh-huh, uh-huh. Okay, she writes like she cooks.

Sheldon: I'll be Coop and he'll be Wheels. If he's okay with that.

Sheldon: Steven Hawking's a genius and he talks like a robot. It's everything I ever wanted in a friend.

Howard: A week ago, I was an astronaut.
Bernadette: Yeah, well, today you're a Smurf! Keep moving!

Stephen Hawking: What does Sheldon Cooper and a black hole have in common? They both suck.

Bernadette: Leonard does things he doesn't like to make you happy.
Penny: Well, yeah he's my boyfriend, isn't that like his job?
Amy: Then what's your job?
Penny: Letting him make me happy.