The One With The Cheap Wedding Dress - S7-E17
Continuity mistake: Chandler's chair appears in this episode again, although it was broken in 7/13 and thrown out. It is not in the room in 7/14-16, but in 7/17 it's there again, then it is gone again in 7/18.
The One With The Stripper - S8-E8
Continuity mistake: In this scene in Central Perk, Monica tells Chandler she has hired a stripper for him as she feels bad for not letting him have a bachelor party, and tells him to think of it as a 2 month anniversary present. However this episode is set 2 episodes after the Halloween episode, therefore allowing us to assume it is set sometime in November or later. Chandler and Monica got married in May, as stated several times in the show by the cast, therefore they have been married for around 6 months or more, not 2 months. (00:07:00)
The One Where Chandler Can't Remember Which Sister - S3-E11
Continuity mistake: When Rachel gets off the phone with Mark she sets the phone on the counter. In the next shot the phone is in the holder and it keeps going in and out.

The One Where Ross Can't Flirt - S5-E19
Continuity mistake: When Ross first tries to flirt with the pizza girl he has money in his hand. When Chandler walks over he gives his own money for the pizza, she leaves, and Ross still has his money. In the next shot when he shuts the door, his hands are empty, then it is back in the next shot when Ross yells at Chandler.

The One With Monica and Chandler's Wedding, Part 1 - S7-E23
Continuity mistake: When Monica and Chandler are talking about what his father might wear to the wedding, the door to their bedroom opens itself and then closes itself between shots.
The One With The 'Cuffs - S4-E3
Continuity mistake: Rachel is telling Chandler to break off his relationship with Joanna, who had walked through the room and went into Chandler's bedroom, shutting the door. By the end of the conversation between Chandler and Rachel, the door is open but no one has entered or left the room.
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 Where Heckles Dies - S2-E3
Continuity mistake: When the gang and Mr Treeger watch the paramedics take Mr Heckles away, a thin dark object like a camera mark or a pencil suddenly appears on the floor close to Ross' feet. (00:03:25)
The One Where the Monkey Gets Away - S1-E19
Continuity mistake: At the beginning when Rachel and Monica talk about the free coffee sample, Rachel puts it down on the counter to her right. In the next shot it's lying to her left with no time to have gotten there. After that it switches from the right to the left and back again. (00:01:25)
The One With All The Cheesecakes - S7-E11
Continuity mistake: Just after Rachel has tried to whistle and just blew out crumbs, she picks up the fork with her left hand and places it to the left of the cake on the kitchen counter. In the next shot just before Chandler picks up the cake the fork is back on the right side of the cake near her right hand. (00:16:05)
The One with George Stephanopoulos - S1-E4
Continuity mistake: When Ross wrestles his puck away from the little kid in the emergency room, it goes flying at the receptionist. The shot cuts, and it hits her from a completely different angle.
The One With The Free Porn - S4-E17
Continuity mistake: In the scene where Phoebe tells the gang about her "Relaxitaxi" idea the position of Chandler's left arm changes between shots. In the frontal shots it's lying the back of the chair and in the shots from behind it's wrapped around Monica's shoulder.

The One Where Chandler Can't Cry - S6-E14
Continuity mistake: In the beginning of the episode when Joey tells Chandler that he hasn't forgiven him for kissing one of his sisters, Monica and Chandler's TV, entertainment set and ferns are missing from the set and there are cables protruding from the wall. The area is completely bare except for the French poster. Everything's back to normal slightly later in the episode.

The One With the Pediatrician - S9-E3
Continuity mistake: Joey's date eats the two olives from her martini, but in the next shot she suddenly has the two olives in her drink again.
The One With Two Parties - S2-E22
Other mistake: When Ross is at Monica's party getting Mr. Green's glasses and cigarettes he bumps into Mrs. Green and ends up having to come up with an alibi for the glasses and cigarettes. He then puts the glasses on, puts a cigarette in his mouth and says 'In fact I'm gonna go out into the hallway and fire up this bad boy'. At this point he walks past Rachel but he stops still as if frozen mid-step just before the shot cuts to him walking out into the hallway.
The One With Phoebe's Ex-Partner - S3-E14
Continuity mistake: When Ginger leaves after finding Chandler's third nipple, she is taking her coat and her purse is lying on the counter. When the camera angle changes, the purse is suddenly in her hand.
The One With Ross's Wedding, part 2 - S4-E24
Continuity mistake: Joey is in their hotel room asking Chandler where Monica is, and the open bathroom door behind Chandler alternates from wide open to halfway open between shots.
The One Where Estelle Dies - S10-E15
Continuity mistake: Just after the opening titles cut to Central Perk, four people can be seen having a conversation through the window. In the next shot, there is one person sitting next to the window and a waitress has appeared out of nowhere. (00:03:05)

The One Where Nana Dies Twice - S1-E8
Visible crew/equipment: When the scene cuts from Joey and Mr. Geller watching the game, to several people watching the game, a boom mic is visible at the top of the screen and the camera tilts slightly. (00:19:00)
The One With All The Candy - S7-E9
Visible crew/equipment: After Ross gives Phoebe the bike and she is leaving to ride it for the first time, the stage lights are visible in the rear view mirror.
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