The One With the Pediatrician - S9-E3
Continuity mistake: After Rachel's 3 AM phone call to her pediatrician, when Rachel suggests using Dr. Gettleman she raises her left hand and points at Ross, but in the next closeup it's her right arm that's raised.
The One With the Pediatrician - S9-E3
Continuity mistake: Joey's date eats the two olives from her martini, but in the next shot she suddenly has the two olives in her drink again.
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