
The One Where Emma Cries - S9-E2
Continuity mistake: When Rachel wakes up Emma during a nap, against Phoebe's advice, there is a shot of Emma in the cot. She is wearing a plain pink hat, but in the next shot, when Rachel lifts her out of the cot, she is wearing a white hat with what looks like little flowers on it. (00:05:55)

The One Where Emma Cries - S9-E2
Continuity mistake: When Ross and Rachel are talking about which muffin she wants, her sleeves move up and down her arms with the different shots. (00:04:45)

The One Where Emma Cries - S9-E2
Continuity mistake: When Joey is seen apologising in front of the hospital room door, we can see a pink wall only about 2 metres behind him. However, in every scene before that which features the door, we can see it leads out to a large open area.
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