The One With Rachel's Crush - S4-E13
Audio problem: In the scene where Rachel walks into the guy's new apartment and they start talking about Joshua, it cuts to a shot of her in profile as she says "It's just so frustrating". Her mouth doesn't move as she says the words. (00:09:40)
Answer: Usually by the seventh night of Hanukkah you don't know what to get the other person, and you will probably resort to getting the other person something insignificant. Chandler is basically saying that the pen is a stupid gift.