The One Where Ross Is Fine - S10-E2
Factual error: If Ross really was holding the sizzling fajitas like that for as long as he was without any gloves, he would be in the emergency room.
The One After Joey And Rachel Kiss - S10-E1
Factual error: The main part of the episode is played out in Chandler & Monica's hotel room (which is situated in between Rachel's and Ross's rooms). The window is opposite the audience and the door on the right. However whenever we see inside Ross's hotel room, he has a window opposite the audience as well. This is impossible as this should be where the hallway is to get to the main door to Chandler & Monica's room. Also, throughout the episode Monica, Chandler & Phoebe all listen through the walls (on either side of their room) to what the other friends are saying, meaning there must be no gap between Ross's and Chandler & Monica's rooms- making the window in his room geographically impossible.
Factual error: When Rachel is boarding the plane to Paris, the plane's right hand side is being used for boarding. However in all airlines all over the world, they always use the left side for boarding. The right side is a 'service' side.
The One After Joey And Rachel Kiss - S10-E1
Factual error: There is an impossibility with the hotel rooms in Barbados. Ross gets from Monica and Chandler's room to Rachel's room far too quickly for it to be real. Also, when the camera moves between rooms (cutting through the wall), you can see that both Rachel and Ross' rooms are too long. If the walls were where they actually are, they would edge through into Monica and Chandler's room. (00:05:05)
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.