The One With Joey's New Girlfriend - S4-E5
Continuity mistake: When Chandler is chasing Cathy, the mustard on his shirt changes place, size and darkness throughout the scene. (00:11:45)
The One With The Tiny T-Shirt - S3-E19
Continuity mistake: When Joey and Kate are talking for the first time, Joey is holding a mug. Between shots, sometimes he is holding the mug by the handle and sometimes by the mug, with the handle sticking out. (00:04:40)
The One Where Joey Moves Out - S2-E16
Revealing mistake: When Chandler and Joey are arguing, they go into their rooms and slam the doors. By Chandler's door, you can see the wall move. (00:10:35)
The One With The Rumor - S8-E9
Continuity mistake: When Will is demanding yams, it shows Ross looking towards the door; the camera then cuts to Will, and Ross is now looking at Will without time to move his head. (00:11:55)
The One The Morning After - S3-E16
Continuity mistake: In previous episodes we've seen that from the living room there's a short wall just inside Monica's bedroom (presumably to prevent a clear view inside, as her bedroom set isn't normally there). However in this episode when most of the gang are in her room, they're listening right by the door into the living room with nothing in the way. (00:11:25)
The One With The Vows - S7-E21
Continuity mistake: After Monica says "Oooh can we lie in our vows?" it cuts to Rachel then back to Monica leaning on her hands, but when it goes for a close up she is holding the pen in her right hand, there isn't enough time for her to naturally pick it up. (00:03:10)
The One Where Joey Dates Rachel - S8-E12
Visible crew/equipment: In the scene of the classroom, before Ross faints, he says, "Why don't you all" and above his head near the clock, there is a boom mic. (00:18:50)
The One With Ross's Wedding, part 2 - S4-E24
Continuity mistake: When Felicity finds Joey outside the wedding venue she closes the door. But when they start kissing, the door is completely open. (00:35:50)
Continuity mistake: Near the end, when Joey is asking Ross if Bonnie's room will be free tonight, he is pointing his hands at Ross. In the very next shot they are in his pockets. (00:20:50)
The One That Could Have Been, part 1 - S6-E15
Revealing mistake: In the opening credits for both parts, fat Monica jumps on the couch and it lifts up on Chandler's end. If you look carefully at Chandler, you can see him holding one end of the couch with his hand and pressing up with his foot. (00:02:10)
The One With Joey's Fridge - S6-E19
Continuity mistake: When Joey pushes Ross against the fridge, a box falls from the top of the fridge onto the shelf beside it. A few seconds later when Joey turns to Chandler, we can see over his shoulder that the box is back on the fridge. (00:08:55)
The One With Joey's New Girlfriend - S4-E5
Continuity mistake: Chandler is chasing Kathy down the street trying to get her attention. During a close-up of him running, just before the camera cuts away we see a guy's face on the left; when it cuts back to Chandler he runs for a while and then encounters the same guy (the dog-walker). Also, when he finally lands in front of Kathy, there is a bike rider coming towards them, but as the camera cuts back and forth between the two, the rider never passes them. (00:11:30)
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 With Joey's Fridge - S6-E19
Continuity mistake: The handle to the fridge door is on the left, so when it opens the inside is visible. In earlier episodes the handle was on the right and it opened out towards the room, blocking the inside from view. (00:00:05)
The One With The Video Tape - S8-E4
Continuity mistake: When Chandler and Monica are trying to call Greg and Jennie, the water bottles on the table move around. Phoebe and Joey didn't move them, they are drinking from the cans. (00:05:30)
The One with the Dozen Lasagnas - S1-E12
Continuity mistake: During the scene where Phoebe is telling Rachel that Paolo made a pass at her, Rachel unrolls a long length of kitchen roll. During the scene there is a shot over her shoulder where we see that the kitchen roll is as normal and in the next shot we see it unrolled again. (00:15:30)
The One With the Holiday Armadillo - S7-E10
Continuity mistake: When Ross is on the couch telling Ben about Chanukah, Ben's hair varies from shot to shot. In the first shot it's flat and in the next shot it's spiked up at the front. His hair stays spiked up for a few shots and then returns to flat. (00:06:00)
The One With The Apothecary Table - S6-E11
Continuity mistake: The red eraser knob on the magnadoodle changes from one side to the other, when Janine is going out to tell Monica she is sorry. (00:18:00)
The One With Phoebe's Birthday Dinner - S9-E5
Deliberate mistake: Across the whole show, whenever Ross closes his apartment, the door remains unlocked; but in this episode, when he and Rachel go outside, the door locks itself. (00:07:00)
The One Where the Monkey Gets Away - S1-E19
Continuity mistake: After Ross asks Marcel to bring him the rice, he picks up his chopsticks. In the next shot, he is holding a napkin. (00:02:15)
Answer: The statements that she's contradicting (that it is common, it happens to every guy, and it's not a big deal), are the things that a woman commonly says to a man who is suffering from erectile difficulty, typically to assuage his bruised ego. However, most men do not believe that these statements are true, as evidenced by Chandler's outburst. He's so caught up in the proof that women are lying about it that he gives himself away.
Rooster of Doom