The One Where Estelle Dies - S10-E15
Continuity mistake: When Rachel walks in with Emma, Ross is on the laptop. It is straight and on the table, in a later shot,the laptop has moved and is over the edge of the table. (00:18:50 - 00:20:55)
The One With Rachel's Going Away Party - S10-E16
Continuity mistake: The level of beer in Ross' bottle goes up and down between shots as he's talking to Joey at the kitchen table. (00:12:00)
The One With Rachel's Going Away Party - S10-E16
Continuity mistake: When Ross fears that Rachel is going to talk with him, the volume and the color of his beer changes between shots.
The One With Rachel's Going Away Party - S10-E16
Plot hole: In this episode Chandler finds furry black handcuffs, and everybody says that they have never seen them before. How is that possible considering all the people that have moved in and out of that room? How come nobody noticed them when the room and closet were painted green after being pink?
The One With Rachel's Going Away Party - S10-E16
Revealing mistake: The twins are dolls. They don't move, and the way they are being carried indicates they don't weigh much.
Continuity mistake: When Ross and Rachel are standing at Ross' door after Rachel comes over to say goodbye and they are hugging and talking, Ross' right hand changes from being on Rachel's shoulder to on her waist and then back to her shoulder. (00:00:35)
Continuity mistake: When Chandler and Monica are in the birthing room and they have just been told they are having twins, her scarf keeps changing from sitting on her shoulder to being over her shoulder. (00:10:20)
Continuity mistake: When Ross is talking to Phoebe and Joey in Central Perk, a strand of Phoebe's hair keeps getting snagged behind the buttons of her blouse and hanging loose again with her other hair several times during the scene. (00:12:40)
Continuity mistake: When Chandler and Monica are at the hospital holding the twins right before they try and swap babies, there are two hospital tags around Chandler's left wrist which then disappear before re-appearing. (00:15:25)
Revealing mistake: When Chandler and Monica try to change the babies, Courteney Cox's pregnant belly is visible. (00:16:20)
Continuity mistake: When Monica and Chandler walk into the apartment with the twins, 2 very bright yellow soothers keep appearing and disappearing from the babies' mouths. (00:18:50)
Continuity mistake: While Mama Joey is looking for Chick Jr. and Duck Jr., the things pinned to the bulletin board beside the door have vanished when Monica and Chandler walk in, but after Monica walks out to check on the twins everything's back up on the board like it was before.
Revealing mistake: When the first baby is born, Monica and Chandler are asked by the doctor if they would like to cut the umbilical cord. However, just before this line is delivered, the baby is moved and its navel is visible.
Continuity mistake: In the hospital when Erica is giving birth and the camera is on the doctor, the door to the room is closed. However, when the camera angle changes, the door is wide open even though no one had entered or exited.
Revealing mistake: When Phoebe and Ross hit heads while in the cab on the bridge, they only just tap heads. Not enough to make them scream in pain. (00:05:15)
Continuity mistake: On the plane, when Rachel says "She's almost never right," (about Phoebe) you can see the guy's hand is on the armrest. Then a split second later, his hand is about half a feet off the armrest while saying "But she is sometimes." (00:15:15)
Continuity mistake: When the friends put down their keys, the keys' positions change when the camera pans the apartment. (00:25:30)
Other mistake: The photo in Rachel's passport at the airport is not of her. (00:29:45)
Other mistake: When Phoebe and Ross are at JFK, some of the people who are at that airport are the same people who are also at Newark. It's particularly funny to see the people behind Ross and Phoebe at JFK when Phoebe claims they're on their honeymoon, and when it cuts to Rachel at Newark as she's looking for her boarding pass, those same people are there too.
Revealing mistake: When everyone leaves the apartment together for the last time, they show Chandler and Monica with the twins in the stroller, and you can tell they are dolls.
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