Amy: I guess I should have known what I was getting myself into.
Leonard: Don't beat yourself up. You've never lived with anyone before.
Amy: That's true.
Leonard: And you're starting out with Sheldon Cooper. That's like getting your first pet and having it be- I don't know. What's a kind of pet that ruins your life?

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: My mother was at bible study. I walked in the house expecting to find it empty, and I heard a sound coming from my parents' bedroom. When I opened the door, I saw my father having relations with another woman.
Penny: Oh, that's awful!
Sheldon: I know. It's also why I never open a door without knocking three times. I mean, the first one's traditional, but two and three are for people to get their pants on.

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.

Bernadette: Uh, I left my phone downstairs!
Howard: Damn, so did I.
Bernadette: Wait, I have my iPad.
Howard: What are you going to do, e-mail 911?