The One With The Bullies - S2-E21
Visible crew/equipment: When Phoebe goes to visit her father, there is a little dog outside. Phoebe gets back in the car and the dog jumps up the side of it. When he finally gets part way through the window, the top of the dog-handler's head is visible through the car window. (00:07:00)
The One With The Bullies - S2-E21
Continuity mistake: When Phoebe calls by the house with the dog, a woman with a handbag is visible in the background, going into her house. About ten seconds later we see the same woman with the handbag walk towards her house again. (00:15:40)
The One With The Bullies - S2-E21
Revealing mistake: In the scene where Ross, Chandler, and the bullies are fighting in the street, an extra bumps the fire hydrant and it wobbles and slides over. (00:21:55)
The One With The Bullies - S2-E21
Visible crew/equipment: When Chandler falls behind the couch, the mat he lands on is visible.
The One With The Bullies - S2-E21
Continuity mistake: When the fight scene starts, one of the bullies takes off his watch and puts it into his right jacket pocket. When they put all of their jewellery into his cap, he gets his watch out of his right jeans pocket.
The One With The Bullies - S2-E21
Continuity mistake: When the bullies are about to fight with Chandler and Ross, they decide to put all watches and keys into a hat. He takes the hat off and places it down and everyone puts the watches and keys in. The shot changes to a further out view and the bully has a different hat on his head while another hat is still placed where he put it. When there is a closer view of him, there is once again no hat on his head. (00:19:30)
The One With The Bullies - S2-E21
Continuity mistake: A woman and a man in a blue shirt exit the coffee shop twice.
The One With The Bullies - S2-E21
Visible crew/equipment: While driving the cab, Phoebe is wearing a blue shirt. When the car stops suddenly, a crew member wearing a white shirt is visible driving the car.
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.