Leonard: Wait, isn't she the grad student that used to follow him around?
Howard: Oh, yeah. Back before he hit puberty and grew man parts.

Howard: You know, I'm really glad you decided to learn Mandarin.
Sheldon: Why?
Howard: Once you're fluent, you'll have a billion more people to annoy instead of me.

Bernadette: Maybe we should get one of those machines to help her up the stairs.
Howard: You mean a forklift?

Sheldon: Sheldon Cooper does not cry.
Howard: That's true, you'd rust.

Amy: I gave you one job! Keep an eye on him. How hard is that?

Sheldon: Because there's only one of me, I'm more valuable.
Penny: Right.
Sheldon: Although, Amy's already taken me out of my package and played with me.

Amy: Why didn't you tell me?
Bernadette: We didn't want you to worry.
Amy: Should I worry?
Penny: No, come on, it's Sheldon. Nothing is gonna happen.
Amy: That's what you said to me when I started dating him. And then five years later, bingo-bango, something happened.