Continuity mistake: The number on Pheobe's cab changes throughout series 2 and 3. 7E85 and 2X85 respectively.
The One With The Princess Leia Fantasy - S3-E1
Continuity mistake: Near the start when Janice is touching Joey's cheek in his apartment, Joey is seen from the front, and he is not holding anything in his hands. He is then shown from the side and he is holding a box of cookies or something similar. (00:02:25)
The One With The Princess Leia Fantasy - S3-E1
Continuity mistake: When Joey says "we'll call that plan B, all right?", Monica has her chin in her hand. When it cuts to a different angle, she's got both arms on the table. Rachel also goes from having both hands clasped under her chin to having one arm resting on the table and one reaching for coffee. (00:05:10)
The One With The Princess Leia Fantasy - S3-E1
Continuity mistake: When Rachel and Phoebe are in Central Perk talking about the Princess Leia Fantasy, a guy in a yellow shirt and white pants is standing at the bar behind Phoebe. As they talk he walks to the door and leaves, but in the next shot he is standing behind Phoebe again, just as she says "That's the moment when she becomes a woman." (00:08:10)
The One With The Princess Leia Fantasy - S3-E1
Continuity mistake: When Ross and Rachel are arguing about Rachel telling Phoebe about his fantasy, Ross takes a popsicle out of the freezer and bites it. In the next shot, the popsicle is whole again, with no bites, and Ross takes another 'first' bite out of it. (00:11:30)
The One With The Princess Leia Fantasy - S3-E1
Continuity mistake: In the scene where Janice tells Joey they should spend some quality time together, the position of her hair changes from in front of her shoulders to behind several times between shots. (00:13:20)
The One With The Princess Leia Fantasy - S3-E1
Continuity mistake: When Ross gets takes out a Popsicle and says who dated a stripper, he takes a bite of his Popsicle and and the camera cuts to Rachel, then back to Ross and the bite has vanished.
The One With The Princess Leia Fantasy - S3-E1
Continuity mistake: When Janice is talking to Joey about his disliking her, her long hair keeps changing position from hanging down her front to being behind her shoulders and down her back.
The One With The Princess Leia Fantasy - S3-E1
Continuity mistake: In the seen where Monica is shouting "why hasn't he called" she is holding a juice bottle, but when the shot cuts to Phoebe she is holding a glass.
The One With The Princess Leia Fantasy - S3-E1
Continuity mistake: S3E1; Ross is telling Chandler about how woman tell each other everything in Central perk. Chandler puts a book about trout on the table and then talks to Ross, then the camera zooms out and the book has moved more to his left and a coffee mug is in front of it.
The One Where No One's Ready - S3-E2
Continuity mistake: The amount of fat in the glass differs throughout the length of the episode. (00:00:05 - 00:15:00)
The One Where No One's Ready - S3-E2
Continuity mistake: In the scene where Chandler sits on Joey in an attempt to regain possession of his seat, the shirt sleeve on his left arm becomes unrolled and slides down. When he stands up, the camera cuts to face Ross while he is giving out directions, leaving Chandler's back to the audience. Chandler's sleeve is now rolled back up. The sleeve remains rolled for the rest of the sequence. (00:06:30)
The One Where No One's Ready - S3-E2
Continuity mistake: When Joey refuses to give Chandler the chair, Phoebe gets hummus on her dress, but in some scenes the stain is much smaller than others. (00:07:00 - 00:08:00)
The One Where No One's Ready - S3-E2
Continuity mistake: When Ross asks Chandler "you took his underwear?", the angle changes halfway through the line. Chandler's hands go from in front of him to being in his pockets. (00:10:50)
The One Where No One's Ready - S3-E2
Continuity mistake: When Phoebe comes out of the bathroom after trying to get out the hummus stain on her dress, the bathroom door is left wide open. But when Monica is playing her message, the door is suddenly almost shut, though no-one had gone near the door.
The One Where No One's Ready - S3-E2
Continuity mistake: Just before Rachel and Ross are leaving Monica's apartment at the end, Rachel stops by the door but the next shot they're further in the room, then they walk past the door and out.
Continuity mistake: When Pheobe is talking to Ursula's stalker, her hands move places with no time to do so. (00:02:45)
Continuity mistake: When Phoebe is talking to her stalker for the first time, at one point, he tips the flowers to the side when Phoebe says, 'Well, this is awkward,' and he puts his left hand on the end of the stems. In the next shot he is holding them with both hands. (00:02:55)
Continuity mistake: When they are talking about sperm donation, Joey is eating a cracker with jam on it. Between shots it instantly rotates in his hand. You can tell because the jam goes from being on the top to the bottom side, and because of the way he is holding it you can see there is only jam on one side. (00:14:15)
Continuity mistake: Right at the end when Ross hits Chandler with his rolled up magazine, he only folds over one-third of the magazine onto the middle third. When it cuts to him hitting Chandler (without a time delay between him hitting Chandler and folding the magazine) the magazine is fully folded over. (00:21:30)
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.