The One Where Joey Moves Out - S2-E16
Revealing mistake: When Chandler and Joey are arguing, they go into their rooms and slam the doors. By Chandler's door, you can see the wall move. (00:10:35)
The One Where Joey Moves Out - S2-E16
Visible crew/equipment: When Monica, Richard, and Ross arrive at the party, the boom mike is seen at the top of the screen. (00:03:50)
The One Where Joey Moves Out - S2-E16
Continuity mistake: When Joey and Chandler are at Joey's colleague's brunch, you can see a big wall clock in some shots. You can see it when Chandler says: "Wow, there's my fantasy's come true" with the minute hand at five to the hour. Just a few seconds later, when Joey says: "Can you see me in a place like this?" it can be seen when Chandler is in shot, and the minute hand is now at 20 to the hour. (00:05:40)
The One Where Joey Moves Out - S2-E16
Other mistake: When Rachel is showing Phoebe her heart tattoo, the tattoo isn't dressed and covered, nor is the skin around it red or swollen, despite the fact she just finished getting it. (00:14:09)
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