The One With the Male Nanny - S9-E6
Visible crew/equipment: When Chandler says "pity laughs," all the stage lights are reflected in the pots behind him. (00:20:50)
The One With The Fertility Test - S9-E21
Continuity mistake: Just before we see Janice, Monica has her hands on Chandlers chest. When it cuts to the wide shot, her hands are round his neck. When Chandler says 'Aw come on.', her hands are on his chest again. (00:12:50)
The One With The Donor - S9-E22
Continuity mistake: When Monica is asking Zack if he or any of his blood relatives has diabetes, Zack's cutlery changes position twice. In the shot facing him he has his fork in his left hand and his knife in his right. When it changes to a side shot, he is gesturing and doesn't have anything in his hands, without having time to put the cutlery down. Then when it cuts back to a front shot, he picks up his fork, which is now on his right, and starts eating. (00:14:30)
The One With The Mugging - S9-E15
Continuity mistake: When Rachel is asking Joey what he's doing with all the liquid, her drink changes places depending on the shots. (00:14:50)
The One With The Boob Job - S9-E16
Continuity mistake: When Mike goes to leave Phoebe's apartment at the start, he puts his jacket over his arm twice. (00:02:10)
The One With The Blind Dates - S9-E14
Continuity mistake: At the end of the blind date, in shots of Rachel, her date Steve is holding her hand with both of his, but from the reverse angle he's only using one. (00:18:45)
The One In Barbados, part 1 - S9-E23
Visible crew/equipment: After Monica and Phoebe leave, David and Chandler are still at Central Perk and when David comments that Phoebe is still hung up on Mike the camera can be seen at the right side of the screen.
The One With Rachel's Phone Number - S9-E9
Visible crew/equipment: After Chandler has climbed down the fire escape and shows up in the hallway where Joey's been waiting with a baseball bat, when they both walk into the apartment the opening in the wall can be seen beside the door. We can see the opening again after Joey finds Chandler's suitcase.
The One Where No One Proposes - S9-E1
Visible crew/equipment: When Mr. Geller, Ross, and the others are looking at Emma lying in the bassinet in the nursery, in the shot facing the adults as the camera zooms in we can see the edge of the set wall (with clouds and stork) behind them, and the set lighting is visible at the top right corner of the screen.
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 With the Male Nanny - S9-E6
Continuity mistake: When Ross storms into the kitchen, exasperated by Sandy, he is immediately followed by Rachel - but she had just been holding Emma, and there wasn't enough time for her to have given Emma to Sandy before storming into the kitchen. (00:25:00)
The One In Barbados, part 2 - S9-E24
Continuity mistake: In The One In Barbados, part 2, when Ross and Charlie are hiding behind the plant from the other scientists, the drinks they are holding refill themselves and Charlie's ornament in her drink keeps switching sides of the glass. (00:45:10)
The One With The Mugging - S9-E15
Visible crew/equipment: Just before Ross and Phoebe walk into Central Perk after being mugged, as it shows the window from the outside you can see a stage light between the blinds. (00:10:35)
The One Where Emma Cries - S9-E2
Revealing mistake: When Emma starts crying and Rachel picks her up, look at how much the baby is moving when she takes it out of the cot. In the next shot it's suddenly only moving it's head, and very slowly at that. This is because it's a robot - and it's very obvious. (00:06:10)
The One Where Monica Sings - S9-E13
Continuity mistake: When Rachel is talking to Gavin at Ross', her position when she's sitting changes depending on the angle. (00:14:20)
The One With the Male Nanny - S9-E6
Continuity mistake: In The One With the Male Nanny in series nine, near the end of the episode Ross gets a beer when he is argung with Rachel as to whether they should fire him. During shots, the label on the bottle moves round. (00:25:05)
The One In Barbados, part 2 - S9-E24
Continuity mistake: When Monica and Mike play table tennis and Monica says "I think that may have missed the table" there is no one sitting in the chairs behind her. The shot then cuts to Mike and he replies "oh do you?" The shot then cuts back to Monica, she replies "er, yeah" and there are suddenly two people sitting in the chairs behind her. Then in the next shot of Chandler and Phoebe the women who were just in the chairs are now walking behind Chandler and Phoebe in the direction of the chairs, and in the next shot they take their seats. (00:38:40)
The One With Phoebe's Rats - S9-E12
Continuity mistake: Extended version. As Rachel says "the guy hates me", in a wide shot Monica turns to her with her arms by her sides to say "does he?". It then cuts to a shot more focused on Monica where she laughs, and she's now reaching forwards to the table. (00:13:10)
The One Where No One Proposes - S9-E1
Revealing mistake: When the nurse hands Emma to Rachel, you can tell it's not a real baby. (00:08:10)
The One With Christmas in Tulsa - S9-E10
Continuity mistake: After Chandler says "Merry Christmas" to the gang, they all respond - Phoebe just goes "blargh blargh", and has her hands in her lap. They all turn to look at her, and suddenly her hands are resting on the sides of the stool. (00:10:30)
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