The One with the Candy Hearts - S1-E14
Continuity mistake: Just before Carol and Susan enter the restaurant, Ross reaches for the menu with his left hand and his right hand is under the table. In the next shot his right hand is holding onto a cup on the table. (00:11:20)
The One with the Candy Hearts - S1-E14
Continuity mistake: In the restaurant when Ross asks Carol to join him, his date has her hand with the chopsticks in it up on the table. In the next shot it is gone. (00:14:55)
The One with the Candy Hearts - S1-E14
Continuity mistake: Just after Rachel throws a bread roll at Joey, he turns to Chandler to speak to him. Chandler is holding his hands out in front of him. In the next shot, his right hand is touching his face, then in the next shot, it is lowered again. (00:02:55)
The One with the Candy Hearts - S1-E14
Visible crew/equipment: Just as Joey and his date are leaving, a stage light and the top of the set drop into view above Chandler. (00:08:10)
The One with the Candy Hearts - S1-E14
Revealing mistake: When Rachel pours the rest of Palo's stuff in the fire, it's clear she pours it on the table not the fire. However, the flames billow up. (00:13:40)
The One with the Candy Hearts - S1-E14
Continuity mistake: When Chandler are Joey are talking in the restaurant and Chandler says "Me and you 'we'" his right hand is raised, camera changes and it's lowered. (00:07:30)
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.