The One Where Ross Finds Out - S2-E7
Continuity mistake: When Rachel finds out that Ross and Julie are getting a cat, watch Rachel's neck. When she says "together?" she's not wearing a necklace; cut to Ross and Julie for a fraction of a second, then when it cuts back to Rachel saying "both of you?" she's suddenly wearing a necklace. It then disappears again when she says "isn't that just lovely?" hanging off the side of the tray she's holding. (00:05:15)
The One Where Ross Finds Out - S2-E7
Continuity mistake: When Rachel finds out that Ross and Julie are getting a cat, watch Rachel's tray. When she says "together?" she's got a towel that is flat; cut to Ross and Julie for a fraction of a second, then when it cuts back to Rachel saying "both of you?" it's now in a pyramid. (00:05:15)
The One Where Ross Finds Out - S2-E7
Other mistake: When Rachel leave her message on Ross' answering machine she mentioned the name Michael after 17 seconds and "I'm over you" after 25 seconds. When Ross listen to the tape he asks "Who is Michael ?" after 8 seconds. Rachel flips the phone out of his hand after 18 seconds so he couldn't have heard her "I'm over you." (00:10:35 - 00:12:50)
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