The One With The Ball - S5-E21
Continuity mistake: When Rachel mentions the cat's name, Ross has the ball. The camera does an instant cut, and Joey now has the ball. Ross did not throw the ball, as you hear the ball being caught every other time. (00:04:50)
The One With The Ball - S5-E21
Continuity mistake: Joey goes into the bathroom and the toilet is behind the door. In a previous episode, when Joey doesn't know about Chandler and Monica, he comes out of his room and thinks it is morning. He goes into the bathroom and Chandler pushes the door open to reveal Joey asleep on the toilet with his toothbrush in his mouth, only the toilet is now on the other side of the room, not behind the door. (00:05:20)
The One With The Ball - S5-E21
Continuity mistake: In the interrogation room, the blinds behind Phoebe keep going from open to closed in different shots. (00:14:10)
The One With The Ball - S5-E21
Continuity mistake: When Monica says "Let's go team Monica!" Joey is holding the ball; when the camera angle changes Chandler has the ball and throws it behind him for someone else to catch. (00:18:15)
The One With The Ball - S5-E21
Continuity mistake: When Rachel is outside the coffee shop trying to sell the cat, in between shots, it goes from a standing to sitting position multiple times.
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