The One With Chandler's Dad - S7-E22
Continuity mistake: When Ross and Rachel are out in the Porsche it is dark outside, but when it later cuts back to Joey in his apartment stealing Rachel's underwear it is broad daylight. It is also light outside when Joey and Phoebe are talking at the coffee house later on. (00:10:30)
The One With Chandler's Dad - S7-E22
Continuity mistake: When Monica and Chandler are in Las Vegas watching the burlesque show, Chandler turns the light on the middle of the table off to "hide" from his Dad. When Monica calls out saying "Waiter. Waitress.", the light is suddenly back on and remains on for the rest of the scene. (00:15:50)
The One With Chandler's Dad - S7-E22
Continuity mistake: When Monica receives her gift from his father, the Porsche, it's gray. When Rachel takes the keys from Ross' jacket and gets into the car in this episode, the Porsche is black. (00:04:49)
The One With Chandler's Dad - S7-E22
Continuity mistake: When Monica and Chandler are in Vegas waiting for the show to start, Monica's wrap goes from high up on her shoulders to half way down her upper arms between shots. This happens more than once. (00:12:40)
The One With Chandler's Dad - S7-E22
Continuity mistake: When Joey is talking about all the different fabrics, the magazine Phoebe is holding keeps changing position. (00:17:00)
The One With Chandler's Dad - S7-E22
Continuity mistake: When Ross is in the car with Rachel he sat in the back you can see him he has his arms crossed and then when the camera cuts to the front view he is holding the seat in front. (00:04:50)
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