The One With Monica's Thunder - S7-E1
Continuity mistake: Chandler is in Rachel's apartment after he has just left Monica; he says to Rachel, "You look great", then Rachel puts her hair behind her ears. The camera cuts to Chandler, then straight back to Rachel, and her hair is not behind her ears. (00:05:05)
The One With The Ball - S5-E21
Continuity mistake: Joey goes into the bathroom and the toilet is behind the door. In a previous episode, when Joey doesn't know about Chandler and Monica, he comes out of his room and thinks it is morning. He goes into the bathroom and Chandler pushes the door open to reveal Joey asleep on the toilet with his toothbrush in his mouth, only the toilet is now on the other side of the room, not behind the door. (00:05:20)
The One With All The Resolutions - S5-E11
Continuity mistake: When Joey and Rachel are trying to work out if the other knows about Monica and Chandler, they sit at the table in silence. In a side shot of Joey they look at each other sneakily, and Joey has his arms by his sides. It then cuts to a head-on shot of Joey, and he's got his right arm over the back of the chair. (00:19:00)
The One With the Male Nanny - S9-E6
Continuity mistake: When Ross walks in on Sandy and Joey playing the recorders, Joey puts his recorder down on the table in front of him, when Ross storms out of the room, the recorder is in a totally different position and also on the far end of the table. (00:24:55)
Continuity mistake: When Monica and Chandler walk into the apartment with the twins, 2 very bright yellow soothers keep appearing and disappearing from the babies' mouths. (00:18:50)
Continuity mistake: Just as Ross and Mona are about to dance, her arms are crossed. The camera cuts and they are on her hips. (00:16:05)
The One Where No One's Ready - S3-E2
Continuity mistake: When Joey refuses to give Chandler the chair, Phoebe gets hummus on her dress, but in some scenes the stain is much smaller than others. (00:07:00 - 00:08:00)
The One With Monica's Thunder - S7-E1
Continuity mistake: In the scene where Phoebe is telling Joey that his eyes "give him away" he is holding a sandwich; the camera angle cuts to behind him and the sandwich is on the table. (00:15:50)
The One With Princess Consuela - S10-E14
Continuity mistake: When Ross is trying to get Rachel's chair through the revolving doors, he has his right leg on the chair but it suddenly switches to him having his left leg on the chair. (00:15:25)
The One With All The Candy - S7-E9
Revealing mistake: At the start of the episode, when Ross says, "No, one daddy, two mommies," Ben is mouthing the line along with him. (00:00:15)
The One with the Dozen Lasagnas - S1-E12
Visible crew/equipment: When Paulo says goodbye to Phoebe, a boom mic can be seen at the top of the screen bobbing in and out at the top of the pillar. (00:17:45)
The One Where Underdog Gets Away - S1-E9
Continuity mistake: When Rachel serves Joey coffee after he comes into Central Perk wearing make up, she puts the cup down on the far left hand side of the table. As Joey picks it up, it has moved to the far right hand side between shots. (00:02:45)
The One with the Dozen Lasagnas - S1-E12
Continuity mistake: When Ross is on about calling immigration, his hands move with no time to do so. (00:04:05)
The One With Five Steaks and an Eggplant - S2-E5
Continuity mistake: When Ross is giving his toast to Monica, when he's finished he drinks from his glass. Later when Chandler arrives, it is still at the same level. (00:07:10)
The One With Two Parties - S2-E22
Continuity mistake: Just after Rachel goes in to her surprise party in Chandler's apartment, she is talking with Ross and Chandler and says, "Both of them are here?" As she says this, she is facing forwards, yet in the next shot, she is suddenly facing Chandler. (00:08:15)
The One Where Ross Dates a Student - S6-E18
Visible crew/equipment: When Joey walks into Chandler's apartment, Chandler is sitting on the couch talking on the phone. Two microphones are visible. (00:06:20)
The One with the Dozen Lasagnas - S1-E12
Revealing mistake: After Phoebe tells Rachel that Paolo made a pass at her, we see a shot of the outside of Monica's apartment block and Rachel is throwing Paolo's clothes out of the window. Look closely and you can see the clothes have been very badly superimposed on to the background. (00:17:05)
Suggested correction: The show sent a crew to New York to film the clothes being thrown from the same building that is used in establishing shots. In a wide-screen version of the episode, the clothes can be seen being thrown out a window (although in the episode the clothes are supposedly thrown off a balcony).
The One With The Embryos - S4-E12
Continuity mistake: When Ross takes a bite of the cookies, he says they are not good, and puts it back in the box; in the next wide shot he is seen putting it back in the box again. (00:03:15)
The One Where Paul's The Man - S6-E22
Continuity mistake: When Rachel and Paul are on the couch at the cabin, the diet coke Rachel is holding switches (repeatedly throughout the scene) from her left hand to her right. (00:12:00)
The One With The Tiny T-Shirt - S3-E19
Continuity mistake: When Joey says "Pete Chicago", there is a green cup on the table next to him; in the shot immediately after that, he is holding it down in front of himself. (00:09:35)