The One With All The Wedding Dresses - S4-E20
Visible crew/equipment: When Ross asks Rachel how she feels about him marrying Emily, several stage lights can be seen in the reflection of the TV during the entire scene.
The One Where Joey Dates Rachel - S8-E12
Visible crew/equipment: In the scene of the classroom, before Ross faints, he says, "Why don't you all" and above his head near the clock, there is a boom mic. (00:18:50)
The One With The Dirty Girl - S4-E6
Visible crew/equipment: When Rachel says, "And not a coupon for an hour of Joey love," the stage lights are reflected in the tv. (00:04:50)
The One With The Ultimate Fighting Champion - S3-E24
Visible crew/equipment: When the friends are leaving for dinner, and Phoebe stops Rachel to ask her about Bonnie, the stage lights are reflected in the TV. (00:06:00)
The One With The Mugging - S9-E15
Visible crew/equipment: Just before Ross and Phoebe walk into Central Perk after being mugged, as it shows the window from the outside you can see a stage light between the blinds. (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 with the Dozen Lasagnas - S1-E12
Visible crew/equipment: When Chandler and Joey are talking about buying a table, a line of stage lights is visible in the tv. (00:07:25)
The One With Rachel's Date - S8-E5
Visible crew/equipment: As Phoebe walks into the restaurant kitchen, a crewmember's hand is visible stopping the door from swinging too much. (00:16:50)
The One Where Rachel Quits - S3-E10
Visible crew/equipment: When Monica, Ross, Chandler and Rachel are at the apartment and Rachel is suggesting how funny Chandler is, as soon as Ross says, "Sweetie, calm down it's going to be OK," a boom mic can be seen for a short period of time, at the top of the screen. (00:13:35)
The One With Phoebe's Ex-Partner - S3-E14
Visible crew/equipment: When Monica and Chandler are discussing the date he had with Ginger, when he says, "She's great looking," two stage lights are visible in the background. This mistake is visible for a long period of time, where it's slightly visible, shown in shadows, and largely visible as Chandler and Monica are talking. (00:14:30)
The One With Joey's Award - S7-E18
Visible crew/equipment: When Monica and Chandler are talking in the living room, Monica asks if there is 'anything you'd like to talk about, or share.' On the left of the screen the shadow of a boom mic can be seen moving on the lounge cushion. (00:17:20)
The One With The Proposal, part 2 - S6-E25
Visible crew/equipment: When Chandler walks in and sees Monica, the boom mic is visible above Monica's head. (00:17:45)
The One With The Blind Dates - S9-E14
Visible crew/equipment: At the start in the coffee shop there are some stage lights visible in the coffee pot behind Joey. (00:00:05)
The One With The Embryos - S4-E12
Visible crew/equipment: When Rachel is protesting that she loves her apartment, look very carefully towards the top of the screen on the long shot of Monica and Rachel before it zooms in and you will see the shadow of a microphone move swiftly across the wall. (00:17:40)
The One With Princess Consuela - S10-E14
Visible crew/equipment: At the very beginning of the episode when the friends are at the table a microphone dips into the shot above the table. (00:00:05)
The One with Two Parts: Part 1 - S1-E16
Visible crew/equipment: When Rachel is taking the Christmas lights down, a boom mic is visible as the camera pans down when we first see her. (00:21:15)
The One Where Ross Dates a Student - S6-E18
Visible crew/equipment: Just after Ross' girlfriend leaves the Central Perk, Ross walks towards the couch. Just before Rachel starts talking, the stage lights can be seen reflected in the glass above the entrance. (00:17:00)
The One In Vegas, Part 1 - S5-E23
Visible crew/equipment: When Ross is leaving Rachel's, a stagelight can be seen by the bathroom. (00:12:00)
The One With Joey's Bag - S5-E13
Visible crew/equipment: When Joey walks into Monica's apartment the first time, a stage light can be seen by the window near the bathroom. (00:10:00)
The One Where Underdog Gets Away - S1-E9
Visible crew/equipment: When Monica shuts the TV off while watching skiing, there is a closeup of the screen as it goes blank. You can see reflected in the blank screen an image of a man in a long sleeved shirt and tie, who does not correspond to any of the characters in the room. (00:08:00)
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