The One With The Embryos - S4-E12
Visible crew/equipment: When Rachel crosses the boys' apartment to see what is in the drawer, if you look up to the right, you can see a glimpse of a boom mic. (00:20:25)
The One With Chandler In A Box - S4-E8
Visible crew/equipment: When Chandler is telling the friends the meaning of the box, the camera goes a bit too high and all the stage lights and equipment become visible on the ceiling. (00:12:30)
The One With All The Wedding Dresses - S4-E20
Visible crew/equipment: After Ross announces that he and Emily will be getting married in a month, there's a shot of Joey and Chandler, and when it cuts back to Ross saying, "Yup!" the reflection of the boom mic can be seen on the framed picture hanging on the bathroom door.
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 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 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 Ross's Wedding, part 1 - S4-E23
Visible crew/equipment: When Rachel gets back from shopping, all the stage lights can be seen in the tv. (00:11:50)
The One With The Jellyfish - S4-E1
Visible crew/equipment: When Ross storms out of the room and the rest of the friends are in the kitchen, you can see the stage lights at the top of the screen. (00:20:15)
The One With Ross's Wedding, part 1 - S4-E23
Visible crew/equipment: In the scene where Phoebe and Rachel are discussing whether she loves Ross, the stage lights are visible in the TV. (00:07:25)
The One With Ross's Wedding, part 1 - S4-E23
Visible crew/equipment: When Rachel exits her bedroom and says she's going to London, you can see tape markings on the floor by her bedroom door and the end of the set. Furthermore, you can see a chair which is likely part of the Central Perk set. [Widescreen version]. (00:20:25)
The One With Rachel's Crush - S4-E13
Visible crew/equipment: When Rachel comes in at the start of the episode a stage light is reflected in the TV. (00:02:05)
The One With The Dirty Girl - S4-E6
Visible crew/equipment: When Monica leaves the kitchen into the next scene, the boom mic is visible at the top of the screen above the kitchen door for a short period of time. (00:07:40)
The One With The Worst Best Man Ever - S4-E22
Visible crew/equipment: After Phoebe gets very annoyed by the leather pants gift, when she stands up and walks to the bathroom the boom mic can be seen at the top of the screen, just as she pulls the crepe streamer down.
The One With The Worst Best Man Ever - S4-E22
Visible crew/equipment: After Phoebe looks down at her belly and scolds the triplets for kicking one another, when Joey walks in and asks if he can borrow a big bowl, studio lighting rigs can be seen at the top right side of the screen.
The One With Chandler In A Box - S4-E8
Visible crew/equipment: When Monica and Tim are on the balcony, we can see the end of the set wall, as well as studio equipment and lighting, at the left side of the screen.
The One With Ross's Wedding, part 1 - S4-E23
Visible crew/equipment: When Rachel opens the door to the apartment while she's holding flowers and sees Phoebe trying to get up from the couch (before the wedgie comment), the open edge of the set wall can be seen at the top left corner of the screen.
The One With Chandler In A Box - S4-E8
Visible crew/equipment: After Joey tells Chandler he's going to his folks and might stay there for a few days while looking for an apartment, just as Joey retrieves his keys from the shelf, a crew member wearing a black shirt and white pants is visible on the left side of the screen. (00:08:40)
The One With Chandler In A Box - S4-E8
Visible crew/equipment: When Chandler is climbing out of the box, you can see the bottom of the set spotlight right above the bathroom door. (00:20:35)
The One With The Embryos - S4-E12
Visible crew/equipment: In the shot where Monica suggests that Ross creates the questions, there is a red boom mic followed by a blue boom mic at the top center of the screen. (00:05:15)
The One With Chandler In A Box - S4-E8
Visible crew/equipment: Just as Ross asks Rachel for the necklace he got her, a stage light is very visible above the bathroom door. (00:12:35)
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