Sheldon: What the hell do you mean, dead end?
Dennis Kim: I mean, the whole landscape of false vacuums in string theory could be as large as ten to the five-hundredth power. In addition ... ooh, look, chocolate milk.
Sheldon: I sense a disturbance in the force.
Leonard: (Imitating Yoda) A bad feeling I have about this, mmm-hmmm.

Leonard: What would you be if you were attached to another object by an inclined plane, wrapped helically around an axis?
Sheldon: Screwed?
Leonard: There you go.

Sheldon: This song is never going to stop. Have you ever dealt with something so relentlessly irritating?
Leonard: That's a trick question, right?

Leonard: Penny, as a scientist, my job is to figure out why things happen. But I don't think I'll ever understand how someone like me could get to be with someone like you. You know maybe I don't need to understand it, I just need to be grateful. I love you, Penny.

Raj: Can you believe it! He watched me work for 10 minutes and than he tried to build a little piece of software that could replace me.
Leonard: Is that really possible?
Raj: As it turned out, yes.

Sheldon: Engineering. Where the noble semiskilled laborers execute the vision of those who think and dream. Hello, Oompa-Loompas of science.

Leonard: Okay, Sheldon, I understand that youre going through a bit of a career crisis, you're searching for some other area where you can feel valuable and productive but I need to tell you something and I want you to listen carefully.
Sheldon: All right.
Leonard: Go away!