The One With Ross's Tan - S10-E3
Continuity mistake: At the start, the lid on Joey's bottle is on and off depending on the shot. (00:00:20)
The One With Ross's Tan - S10-E3
Continuity mistake: Ross' tan keeps changing shades. It gets lighter then darker, then lighter again. (00:12:40)
The One With Ross's Tan - S10-E3
Continuity mistake: When Ross gets a spray on tan, there is one shot where he is being sprayed in the face. Instant camera cut then it's on his chest, not near his face. (00:19:35)
The One With Ross's Tan - S10-E3
Continuity mistake: Chandler walks away from Ross's apartment at the end. But he walks to where the kitchen should be. (00:21:15)
The One With Ross's Tan - S10-E3
Continuity mistake: In the scene where Joey and Rachel are sitting on the couch in their apartment after they decide their relationship is hopeless Rachel puts her head on Joey's shoulder. Her hair is on her face but when she lifts her head up in the very next shot her hair is now behind her right ear which she couldn't have done because her hands never left her lap. (00:22:00)
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.