The One With The Soap Opera Party - S9-E20
Continuity mistake: When Rachel is confronting Joey about the secret party the water bottle in her hand changes from her left to her right hand back to her left again. (00:06:10)
The One With The Soap Opera Party - S9-E20
Revealing mistake: When on the roof for the party, the view of the city is obviously fake. (00:12:20)
The One With The Soap Opera Party - S9-E20
Continuity mistake: When Ross is telling Rachel and Phoebe about Charlie's past boyfriends, he refills two wine glasses. Then in the next shot, he puts his hands to his cheeks in shock because he just remembered something, without putting the wine bottle on the table. It just disappears from his hands. (00:16:05)
The One With The Soap Opera Party - S9-E20
Visible crew/equipment: After Ross introduces Charlie to Phoebe and Monica in Monica's' apartment Charlies' cell phone rings. She turns around and in the back where the "secret closet" is, you can see on the left corner two spotlights.
The One With The Soap Opera Party - S9-E20
Other mistake: In the opening credits, the word "Teleplay" is misspelled as "Telelplay."
The One With The Soap Opera Party - S9-E20
Other mistake: When Rachel walks in to her apartment right before the message of Jan Rogers, you can see the hole in the wall where the board usually is.
The One With The Soap Opera Party - S9-E20
Visible crew/equipment: When the roof party begins, above the door a boom mic is visible.
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