tragi-comédia sobre a corrida às prendas de Natal (obrigada, A.)

Penny: [after the tale of Saturnalia] Okay, well, thank you for that, but I got you and Leonard a few silly neighbor gifts, so I'll just put them under my tree.
Sheldon Cooper: Wait! You bought me a present?
Penny: Uh-huh.
Sheldon Cooper: Why would you do such a thing?
Penny: I don't know. 'Cause its Christmas?
Sheldon Cooper: Oh, Penny. I know you think you are being generous, but the foundation of gift giving is reciprocity. You haven't given me a gift. You've given me an obligation.
Howard Wolowitz: Don't feel bad, Penny, it's a classic rookie mistake. My first Hanukah with Sheldon, he yelled at me for eight nights.
Penny: Now, hey, it's okay. You don't have to get me anything in return.
Sheldon Cooper: Of course I do. The essence of the custom is that I now have to go out and purchase for you a gift of commensurate value and representing the same perceived level of friendship as that represented by the gift you've given me. It's no wonder suicide rates skyrocket this time of year.
Penny: Okay, you know what? Forget it. I'm not giving you a present.

(from "The Big Bang Theory")