The One In Vegas, Part 1 - S5-E23
Visible crew/equipment: After Phoebe tells Chandler that Monica wants to make up and that he needs to find her, when Chandler leaves the room we can see the end of the set wall, with the hallway and another hotel room door, at the left side of the screen.
The One With Rachel's Inadvertent Kiss - S5-E17
Continuity mistake: When Joey is counting the floors of Ross' building (the first time) to find out where Hot Girl lives, he is wearing a black top with a zip. When he rushes over to Ross' building he walks down the hall and knocks on what he believes to be Hot Girl's door. In these shots he is wearing a dark purple button up shirt. As soon as Ross answers the door, Joey is wearing the black top with a zip again. (00:03:15)
The One In Vegas, Part 2 - S5-E24
Visible crew/equipment: At the start of the Netflix version, when the recap scenes from 5x23 Part 1 are being shown, in the shot of Phoebe, Monica, and Chandler on the airplane the end of the cabin set can be seen beside Chandler, at the right side of the screen.
The One In Vegas, Part 1 - S5-E23
Visible crew/equipment: While Phoebe, Monica, and Chandler are with gladiator Joey in the casino, Joey notices the tension between Chandler and Monica, and when he asks what's going on a tape mark can be seen on the floor at the feet of the extra standing at the slot machine, then more tape marks can be seen at the same spot after Monica sarcastically wishes Chandler happy anniversary.
The One With Chandler's Work Laugh - S5-E12
Visible crew/equipment: After Joey and Phoebe place their betting cash on the counter, when Joey says, "Let's get the contestants out of their isolation booths," the end of the set wall can be seen behind the foosball table. (Widescreen version).
The One In Vegas, Part 1 - S5-E23
Visible crew/equipment: When Phoebe, Monica, and Chandler walk into Caesars Palace Casino, Phoebe notices Joey, and in the next wideshot we can see the camera panning around (it's on a camera crane, presumably filming the overhead angle seen in this scene), at the top right corner of the screen. (Widescreen version).
The One With All The Resolutions - S5-E11
Visible crew/equipment: After Monica and Chandler leave the apartment to go "do laundry," Rachel and Joey tell each other that they can't share what they each know, and just as Rachel sits down beside Joey, we can see the movement of camera equipment in the window's reflection, above the sink.
Continuity mistake: In the beginning of the episode Chandler opens the door to the bathroom and Joey is sitting on the toilet. This is the only episode the toilet is positioned there. It is normally behind the door in other episodes.
The One With Joey's Big Break - S5-E22
Factual error: Joey and Chandler are supposedly crossing the George Washington Bridge but the exterior background viewed from inside the car is very obviously a repeat reel of another bridge, and their conversation goes on for far too long for the actual crossing. And the cutaway shot after Chandler is kicked out of the car shows an aerial view of the Brooklyn Bridge.
Visible crew/equipment: When Ross notices that Ugly Naked Guy is back, in the next exterior shot we can see the top of the set as everyone gathers at the window.
The One With All The Resolutions - S5-E11
Visible crew/equipment: After his fiasco with the leather pants, powder, and lotion, when Ross is at Monica's and tells the others he's going to kiss Ben goodnight, as he starts walking to the bedroom the camera can be seen at the right side of the screen.
The One With Ross's Sandwich - S5-E9
Continuity mistake: After Joey makes up the story about how he slept with Monica once in London, in the shots facing Phoebe, Rachel, and Ross the door to Monica's apartment goes back and forth being either wide open or closed, depending on the angle of the shot.
The One With All The Thanksgivings - S5-E8
Continuity mistake: In the flashback where Joey sticks the turkey on his head, the subtitle says Thanksgiving 1992. However, the show started in 1994 and Joey didn't move in until the previous fall, so the earliest Thanksgiving that he was there would have been 1993. (00:04:30)
The One With Joey's Bag - S5-E13
Continuity mistake: When Phoebe is in the coffee house talking to her father and pretending to be the executor of her grandmother's will, after she says "lipstick and a daughter, big day for you" she folds her papers in half, but in the next shot they are unfolded and she then folds them again. (00:15:15)
The One With The Ball - S5-E21
Continuity mistake: In the interrogation room, the blinds behind Phoebe keep going from open to closed in different shots. (00:14:10)
The One After Ross Says Rachel - S5-E1
Continuity mistake: Monica and Chandler are piling their dinner plates with food while arranging to meet for a second quickie. Chandler's plate is stacked with various items when he agrees to meet Monica in the cellar, but when he tosses his plate back onto the table to rush off without eating anything, the plate is nearly empty. (00:04:45)
The One With The Ball - S5-E21
Audio problem: When Rachel is trying to sell the cat and someone looks the hiss is a clear overdub. (00:16:20)
The One In Vegas, Part 1 - S5-E23
Continuity mistake: After Joey tells Chandler about his identical hand twin and plans for getting rich, when he sees Chandler's reaction Joey asks, "Are you unsupporting me again?" while he lifts his left arm and points accusingly at Chandler, but next shot it's Joey's right arm that's up and pointing.
The One Where Ross Can't Flirt - S5-E19
Other mistake: While everyone's watching Law and Order for Joey's big scene, Rachel, Phoebe, Monica, and Chandler are sitting on the couch and Ross is standing behind them, but in the TV's closeup the screen reflection reveals an empty couch.
The One With Rachel's Inadvertent Kiss - S5-E17
Visible crew/equipment: While Joey's looking for the "hot girl" the second time, after he knocks on the little girl's door and asks if her mother, sister, or babysitter are a hot girl, he runs off when she shouts for her father, and when Joey stops in another hallway full of doors the shadow of the moving boom mic can be seen on the door beside him.
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