The One Where Rachel Quits - S3-E10
Continuity mistake: In the classroom Ross has his head down because he didn't want to be called on about the number of boxes he sold. The mother brown bird walks behind him and her right hand is on her hip while she is clearing her throat. In the next shot her right arm is pointing upward.
The One Where Chandler Can't Remember Which Sister - S3-E11
Continuity mistake: Ross is on about going to Maryangela's to Chandler. He picks his drink up, the camera cuts and he picks it up again. (00:12:45)

The One Where Chandler Can't Remember Which Sister - S3-E11
Continuity mistake: When Joey is saying about ticking his Grandma off, he has his hands up in front of him. When the shot changes, his hands are lowered. (00:13:20)
The One Where Chandler Can't Remember Which Sister - S3-E11
Continuity mistake: When Rachel gets off the phone with Mark she sets the phone on the counter. In the next shot the phone is in the holder and it keeps going in and out.

The One With All The Jealousy - S3-E12
Continuity mistake: At the start, Ross says, "Botanists are such geeks." When he does, his left hand goes from in his lap to on the table instantly. (00:00:35)
The One With All The Jealousy - S3-E12
Continuity mistake: When Monica is confronting Julio about the poem, there are two bottles upside down on the top of others. He turns one over, but in the next shot there are still two upside down, and then there are none. (00:15:35)
The One With All The Jealousy - S3-E12
Continuity mistake: When Chandler is showing Rachel his stripper pen, Rachel is sitting with one leg up on the couch. When Ross walks in her legs are crossed, then she takes her leg down off the couch again and crosses them again. (00:18:00)

The One With All The Jealousy - S3-E12
Continuity mistake: In the coffee house when Rachel is talking to Ross about trust, a couple comes in behind her and stands at the bar. In the next shot of Rachel they have switched positions; then they are gone, and you never see them walk past Chandler. (00:19:05)
The One With All The Jealousy - S3-E12
Continuity mistake: When Ross and Rachel are talking about his playdate with the stripper, a lady in a black vest talks to the people at the table behind them, then goes to the bar and shakes hands with a lady in a black jacket. She does all this again in another shot. (00:19:30)

The One Where Monica and Richard Are Just Friends - S3-E13
Continuity mistake: Monica and Richard are squishing tomatoes; when she starts dabbing his shirt with club soda the door behind them leading to Monica's room goes from open to shut between two shots. (00:08:30)

The One Where Monica and Richard Are Just Friends - S3-E13
Continuity mistake: When Monica is dabbing Richard's shirt, the way she is holding the cloth changes between shots. Note the amount over her fingers. (00:08:50)
The One Where Monica and Richard Are Just Friends - S3-E13
Continuity mistake: When Richard sits in Monica's room, when Monica opens the door we can see in the background the living room's window draperies, table, picture frame, etc., but they're not as they should be. In this mock-up the shade is pulled down, the draperies look different, and the direction they're all facing differs. (00:15:55)
The One Where Monica and Richard Are Just Friends - S3-E13
Continuity mistake: When Monica is in Richard's room she lights candles then realises Richard's home with another woman so blows out the candles but misses one. Next she hides under the duvet waiting for Richard. When he comes in all candles are unlit but she is still under the bed. (00:18:00)

The One With Phoebe's Ex-Partner - S3-E14
Continuity mistake: When Phoebe says you never run on a barge, her hand changes position on the table between consecutive shots. (00:06:50)
The One With Phoebe's Ex-Partner - S3-E14
Continuity mistake: When Joey is telling his story about throwing Ginger's wooden leg in the fire, when he gets to the part about him, Ginger and the dog Pepper falling asleep in front of the fire, a large section of her hair falls in front of Phoebe's face. In the next shot it's gone;, however her hands are visible the whole time and she has not pushed the hair back. (00:08:05)

The One With Phoebe's Ex-Partner - S3-E14
Continuity mistake: When Monica comes in and asks Chandler if she can borrow some milk, Chandler is reading a paper that is flat on the bar. In the next shot he is holding it folded, then he lays it on the counter, and suddenly it is in his hands again. (00:14:20)
The One With Phoebe's Ex-Partner - S3-E14
Continuity mistake: When Ginger leaves after finding Chandler's third nipple, she is taking her coat and her purse is lying on the counter. When the camera angle changes, the purse is suddenly in her hand.
The One Where Ross And Rachel Take A Break - S3-E15
Continuity mistake: When Phoebe rushes in at the start she has a coat on. Camera cuts to Monica then back to Phoebe, and the coat is off. There is not enough time to take it off. (00:00:15)
The One Where Ross And Rachel Take A Break - S3-E15
Continuity mistake: When Cloe hands Chandler and Joey the flier, it goes from flat to folded to flat in 2 camera cuts with no time to do it. (00:03:15)
The One Where Ross And Rachel Take A Break - S3-E15
Continuity mistake: When Phoebe and Monica are at Monica's table and Phoebe is trying to convince Monica to go on a date with her date's translator, watch Phoebe's arm. She points at Monica when she says, "Don't call him that; his name is Spackleback Larry", but when the shot changes to a side view of them, she has her arm resting on the table with no time to put it down between shots. (00:06:25)
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