• Penny: Uh, Sheldon, I didn’t see your present.
• Sheldon: That’s because I didn’t bring one.
• Penny: Well why not?
• Howard: Don’t ask.
• Sheldon: The entire institution of gift giving makes no sense.
• Howard: Too late.
• Sheldon: Let’s say that I go out and I spend fifty dollars on you, it’s a laborious activity, because I have to imagine what you need, whereas you know what you need. Now I can simplify things, just give you the fifty dollars directly and, you could give me fifty dollars on my birthday, and so on until one of us dies leaving the other one old and fifty dollars richer. And I ask you, is it worth it?
• Howard: Told you not to ask.
• Penny: Well, Sheldon, you’re his friend. Friends give each other presents.
• Sheldon: I accept your premise, I reject your conclusion.
• Howard: Try telling him it’s a non-optional social convention.
• Penny: What?
• Howard: Just do it.
• Penny: It’s a non-optional social convention.
• Sheldon: Oh. Fair enough.