The One With Phoebe's Husband - S2-E4
Visible crew/equipment: After the opening credits, just as Joey says that it's unbelievable Phoebe can be married, a camera and yellow electrical cord can be seen at the left side of the screen, and a bit of it is still visible in following shots when Monica mentions the cheeseburger.
The One With The Metaphorical Tunnel - S3-E4
Revealing mistake: While Chandler and Janice are in D'Agostino's, some grocery products have their names partially covered, such as Uncle Ben's and Grape Nuts.
The One Where Joey Dates Rachel - S8-E12
Visible crew/equipment: When Ross is wearing roller-blades while teaching his class, just as he points to the map and says, "Here," the second time, there's a hidden crew member that can be seen behind the end of the set wall with the map, at the left side of the screen.
The One With Phoebe's Wedding - S10-E12
Continuity mistake: When Monica and Phoebe are talking about having a harpist versus Marjorie playing the steel drums, the handbag strap over Monica's shoulder vanishes and reappears.
The One With Joey's New Brain - S7-E15
Character mistake: After Susan Sarandon slaps Joey the first time, after he tells her that her character is dying on DOOL, she turns away and right before she is off camera she smiles, instead of maintaining her anger. (00:06:05)
The One After Joey And Rachel Kiss - S10-E1
Visible crew/equipment: After Chandler starts removing Monica's braids from the shower curtain rings, when it cuts to Joey and Rachel walking into their apartment, we can see the hole in the wall at the right side of the screen. And it's seen again when Ross walks in on Rachel and Joey kissing.
The One with the Dozen Lasagnas - S1-E12
Visible crew/equipment: When Rachel's dumping all of Paolo's clothes over the side of the balcony, we can see the apartment's back wall is only half a wall, with the sound stage and equipment at the left side of the screen.
The One with the Monkey - S1-E10
Visible crew/equipment: While Phoebe's talking about David she mentions the movie 'An Officer and a Gentleman, ' and when she tells them that David is kind of like the guy she went with to see that movie, in the following wideshot the boom mic can be seen moving around at the top of the screen. (00:06:10)
The One Where Ross and Rachel...You Know - S2-E15
Visible crew/equipment: While "The Dick Van Dyke Show" is playing on TV, when Rachel walks in and heads over to Ross, a crewmember can be seen at the left side of the screen, behind Phoebe.
The One With All The Haste - S4-E19
Visible crew/equipment: After Joey convinces Chandler to agree to the bet, when Phoebe walks over to the recliners and tells everyone that she has a game, the camera can be seen moving at the right side of the screen. (DVD).
The One With The Fake Party - S4-E16
Visible crew/equipment: While Rachel is talking to Chandler she tries to get Joshua's attention so she pretends to laugh, and in the shot facing Joshua the end of the set wall can be seen, with the brick set wall from Central Perk on the other side.
The One In Vegas, Part 1 - S5-E23
Visible crew/equipment: When Phoebe, Monica, and Chandler walk into Caesars Palace Casino, Phoebe notices Joey, and in the next wideshot we can see the camera panning around (it's on a camera crane, presumably filming the overhead angle seen in this scene), at the top right corner of the screen. (Widescreen version).
The One With the Male Nanny - S9-E6
Visible crew/equipment: After Rachel and Ross hire the new nanny, when it cuts to Chandler walking into Joey's apartment, we can see the opening in the wall beside the door.
The One With The Tea Leaves - S8-E17
Visible crew/equipment: After Monica and Chandler leave the apartment so Joey and Rachel can be alone, Rachel tells Joey that it's nothing and he tells her he's going to take-off, then in the next wideshot the camera can be seen at the left side of the screen. (00:08:30)
The One Where Rachel Finds Out - S1-E24
Visible crew/equipment: After Monica asks Rachel if there's someone else and shouts, "Why the hell are you dumping my brother?," when it cuts to Chandler sitting at the counter, the edge of the set can be seen at the left side of the screen, and also note the front door is wide open for the camera access. Additionally, when Joey joins Chandler at the counter the juice box has black tape covering its brand name.
The One with the Sonogram at the End - S1-E2
Visible crew/equipment: When Ross announces that Carol's pregnant, after Chandler says, "Kind of puts that whole pillow thing in perspective..." in the next shot of Ross and Monica we can see a crew member's sleeve at the left side of the screen. (00:07:30)
The One With The Cake - S10-E4
Visible crew/equipment: After Joey describes Emma's funny Elmo cup to Phoebe, it cuts to Monica and Chandler walking in, and to the right of the door we can see the bulletin board is cut in size partially covering the hole in the wall. Later, when Phoebe and Joey leave after the wind-up toy race not only is this visible again, but through the hole we can see the other hole in Monica and Chandler's wall.
The One Where Monica Gets a Roommate - S1-E1
Continuity mistake: At the end of the episode when Ross picks up his jacket, there is a blue bowl on the small table by the pillar and nothing on the main kitchen table. In the next shot, the blue bowl has moved to the large table. (00:27:10)
The One Where Monica Gets a Roommate - S1-E1
Continuity mistake: The door to Monica's bedroom is shown open, then closed, then open, and then closed during the scene in which Paul arrives for their date. (00:09:00)
The One With The Boob Job - S9-E16
Revealing mistake: When Phoebe and Mike walk into Central Perk and announce they're moving in together, Chandler, Monica, and Ross, who's wearing a sweatshirt and khakis, are all sitting on the couch, and after Phoebe's comment about loading up the Volvo and wanting to be a soccer mom, it's David Schwimmer's stand-in, wearing a blue button-down shirt and jeans, who is seated beside Chandler.
Suggested correction: I've seen a few of these listed as errors, but they're not. A lot of shows do this often if you pay attention. It's called "product displacement", and it is done to avoid being sued or having to pay licensing fees. Also, it is cheaper to alter logos like this than pixelate/blur them out. What is interesting though, is that one of the grape nut boxes in this picture does not have an altered logo.
Yes, it's product displacement, and this is specifically referred to as the "greeking" process. However, your correction only offers an excuse as to why this occurs. The tape or paint partially or fully covering the brand names or logos are a distraction, and it removes viewers from the fake reality of the show or movie. Originally, these types of submissions were to be listed in trivia, but instead they were placed in the mistake section.