The Big Bang Theory2007

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.

Sheldon Cooper:
No, it's too late. I see it. That elf sticker says, "To Sheldon." The die has been cast. The moving finger has writ. Hannibal has crossed the alps.

Howard Wolowitz:
[Raj then whispers into Howard's ear then they both laugh] I know. It's funny when it's not happening to us.

Penny:
[Exasperated] Sheldon, I am very, very sorry.

Sheldon Cooper:
No. No, I brought this on myself by being such an endearing and important part of your life.

[Turning to Howard and Raj]

Sheldon Cooper:
I'm going to need a ride to the mall.

Howard Wolowitz:
It's happening to us.