The One With Rachel's Crush - S4-E13
Other mistake: Monica supposedly single-handedly changed over the guys' apartment from carpet to polished hardwood in two days. There's no way that someone of her size could have moved all that furniture solo (Rachel didn't help since she's totally surprised), stripped off all the carpet, sanded the wood, stained the wood, let it dry, and then replaced all the furniture, in two days.
The One With Rachel's Crush - S4-E13
Continuity mistake: When Monica waves the smell of cookies in the guys' new apartment, you see Ross right in front of Phoebe when they walk over, then you see Ross in front of Rachel as they go in.
The One With Joey's Dirty Day - S4-E14
Continuity mistake: When Rachel is asking Ross if he will take Emily to the opera, the amount of biscuit in his hand changes throughout. (00:06:15)
The One With Joey's Dirty Day - S4-E14
Continuity mistake: When Rachel is telling Monica and Phoebe about her night out with Joshua the previous evening, Monica is holding a glass of orange juice. To begin with the glass is half full, but then changes to being almost full to the top, and then back to half full. (00:09:00)
The One With Joey's Dirty Day - S4-E14
Revealing mistake: After Joey is caught in Charlton Heston's shower, he wraps a towel around his waist and sits on the arm of chair. You can see the line of the Speedo underwear under the towel. (00:15:55)
The One With Joey's Dirty Day - S4-E14
Continuity mistake: In the scene where Mr Heston confronts Joey about using the shower, Mr Heston points at Joey from a seated position. As the shots switch Mr Heston's "pointing" hand also switches. (00:16:30)
The One With Joey's Dirty Day - S4-E14
Visible crew/equipment: When Ross and Joey are explaining phase two of Chandler's break up (going to strip clubs), the camera switches from the girls to Ross and Joey. Behind them is Chandler and Joey's kitchen window where you can briefly see a reflection of someone passing by (crew member). At first I thought it could have been Chandler, since he was not in the scene, but after a few moments you see that Chandler has been in the bathroom the whole time. (01:35:00 - 01:39:00)
The One With Joey's Dirty Day - S4-E14
Visible crew/equipment: After the exterior shot of Bloomingdale's, when it cuts to Rachel helping Joshua with his clothes the camera can be seen at the left side of the screen.
The One With Joey's Dirty Day - S4-E14
Continuity mistake: After Chandler gets back from the strip club, when he throws his jacket and scarf they both land on the rug between the recliner and coffee table, but when Chandler sits in his recliner the jacket is gone and the scarf is lying on the floor on the opposite side of the table.
The One With All The Rugby - S4-E15
Continuity mistake: When Rachel is talking to Joey about flushing the toilet, her hands go from counter to bottle top to counter with no time between camera cuts. (00:02:00)
The One With All The Rugby - S4-E15
Factual error: Rugby starts with a kickoff and not with a scrum, only the forwards on the team participate in the scrum not the whole team, and there is no scrum half to retrieve the ball from the scrum. The scrum took far too long. There is no structure to the scrum like there should be (props, locks, flankers etc). He doesn't seem to have a team and for some reason everyone just jumps on him, there is no line with one team and another it just seems like a free for all which is nothing like rugby, rugby halves are ended when the ball goes out of play which does not happen here - he just decides to end it for no real reason. Several fouls are committed in the ruck such as coming in from the sides, diving off their feet and holding onto the ball which aren't being penalised. You're not allowed to kick people or harm them intentionally in rugby, there are no cups in rugby but there are mouth guards, which no one is wearing.
The One With All The Rugby - S4-E15
Continuity mistake: During the rugby game, when Ross tells Phoebe and Joey that he thinks he's dying there are two hairsticks in Phoebe's bun in the shots facing her, but there's only one hairstick in her bun in the shots facing Ross.
The One With All The Rugby - S4-E15
Visible crew/equipment: When Phoebe walks into the apartment while Ross and Joey are watching rugby on TV, the boom mic and a bit of the overhead studio lighting can be seen right before she sits down, and the boom mic can be seen again when Joey stands up after Chandler walks in with Janice.
The One With All The Rugby - S4-E15
Factual error: Before Ross goes out to play the second half of the rugby game, Emily gives him some tips on how to hurt the other guys. She singles out one of the guys, saying he doesn't wear a cup. These guys are all English players who love rugby. Rugby players would NEVER wear a cup for rugby is more of a grinding sport than hit and miss. These guys would be crazy to wear a cup.
The One With All The Rugby - S4-E15
Continuity mistake: When Rachel comes home and excitedly tells Monica that she felt Joshua's pulse, there are two handbags hanging from Rachel's shoulder which vanish between shots, but then they reappear on her shoulder.
The One With All The Rugby - S4-E15
Other mistake: When Ross first goes out to play rugby and goes into the scrum, just after Emily talks to the rest of the players, he jumps into the middle of the scrum where the ball should be. Instead, in the next shot, the rugby ball is to the far left of the shot, not in the actual scrum.
The One With The Fake Party - S4-E16
Continuity mistake: When Rachel is talking to Joshua near the drinks table at the party, he is holding a blue cup in his left hand and nothing in his right (this is most obvious when she's offering him a cherry). When she begins to choke, he raises his empty right hand to pat her on the back, then when she walks away there is suddenly a bottle in his raised hand. The shot changes, and his hand is again empty and he reaches down to the table and picks up the same bottle. (00:08:30)
The One With The Fake Party - S4-E16
Continuity mistake: When Rachel is in her bedroom dressed as a cheerleader with Joshua, the sleeve of her sweater on her right arm keeps moving up and down. (00:15:00)
The One With The Fake Party - S4-E16
Visible crew/equipment: While Rachel is talking to Chandler she tries to get Joshua's attention so she pretends to laugh, and in the shot facing Joshua the end of the set wall can be seen, with the brick set wall from Central Perk on the other side.
The One With The Fake Party - S4-E16
Continuity mistake: After Rachel explains her plan for the fake party, just as Emily opens the apartment door the message written on the Magna Doodle reads "Joey enjoys the," but when Emily and Ross are standing in front of the door the message reads "Joey eats little."
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