Leonard: I know how to deal with Sheldon being Sheldon, but Sheldon being a-a rational, thoughtful person? I'm clueless. It's like when my mom called last year to sing happy birthday and I-I just threw up.

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.

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.

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

Sheldon: No, the campus isn't safe at night. There's raccoons and undergrads just walking around like they own the place.

Raj: Uh, you know, my secret to making great omelets is that I beat the egg whites separately. Speaking of which, how long have you been separated? Speaking of which, how long have you been separated?
Nell: About two weeks.
Raj: That is not a lot of weeks. In fact, that's the bare minimum to get to the plural "weeks".

Howard: Look at this cute picture of Halley in the bath.
Leonard: Aw, that's great.
Howard: Want me to send it to you?
Leonard: No, on your phone it's cute, on my phone it's a crime.