Continuity: The view from Monica's apartment changes after the first few episodes.

Continuity: The number of the flats near the start of the first series was 4 and 5. After a few shows they changed to 19 and 20. [The producers realised that the numbers 4 and 5 were for apartments on the lower floors and had shown Monica's apartment to be much higher up so they changed the numbers - it's still a mistake but there's the reason.]

Continuity: 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.

Continuity: When Ross, Chandler and Joey are setting up Ross' furniture and Ross is bent down saying, "And I cannot feel my legs," Ross is holding a manual. When it cuts, the manual is on the floor.

Continuity: In the scene where the friends scoot the table over to see Monica's date with "Paul the wine guy", the cup in front of Chandler changes position.

Continuity: 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.

Continuity: When Rachel loses the ring near the beginning, Chandler and Joey get off a chair to help look. But then the shot cuts to Monica, and behind her you can see Chandler at the fridge without enough time to get there.

Continuity: When Rach gets her first paycheck, the envelope is already open, but she then rips it open.

Continuity: Just before Ross gets hit in the hockey game, you can see him wearing a foam finger which then disappears.

Continuity: In the scene just before Joey goes into the shower, when he is thanking the director for the opportunity, the camera shot goes back and forth between Joey and the director several times. During this series of shots, the part in Joey's hair switches sides nearly every time. It appears that the entire shot is reversed - in the closeup, the shower curtain is on his left and the shadow to his right is sharply focused. In the lower (long) shot, the curtain is to his right, and the shadow on his left is more focused.

Revealing: In the episode where Joey is doubling Al Pacino's butt you can clearly see his shadow when he's shooting the scene in the shower, and he's wearing boxer shorts.

Revealing: When Rachel first meets Paolo she's looking for the cat in candlelight, holding the candle in front of her. You can see her shadow on the wall, as well as the shadow of the candle, revealing that the light is not coming from the candle.

Continuity: In the scene where Joey is standing with candelight over Ross' neck, the candle is full length, but in the next shot it's only half length.

Continuity: When Ross falls into the grave he ends up with a massive mud patch on his knee. He turns over and it's gone.

Continuity: When Rachel gets her mail off Monica she puts it down on the couch and picks up a sealed envelope. The camera cuts and the envelope is now open with no time to open it.

Revealing: Whenever Monica's apartment is shot from the point of view of the balcony looking in, fake walls have to be put up across the room to cover the open space (since there is no wall there usually). When the friends are looking out the window at Ugly Naked Guy and his girlfriend in this episode, you can see that the rear wall does not extend nearly far enough - there is a large black space behind Monica.

Continuity: At the end of the episode when Chandler makes a toast, he is holding the glass in his right hand. In the next shot, the glass has jumped to his left hand.

Continuity: When Rachel says about her 6th date with Paulo, she is holding a decoration for the tree. In the next shot the decoration changes to a much larger object. Then, in the next shot, as she hands it to Monica, it has turned back to the original shape.

Continuity: When Ross say 'just a smidge' after Rachel says Paulo named her breasts, Phoebe is holding tinsel and Rachel is looking at Ross. In the next shot, Rachel is looking in the opposite direction and the tinsel has vanished from Phoebe's hands.

Continuity: Just after Chandler explains the situation to Janice, she goes off crying, and Ross takes a photo. The flash is much brighter than it should be - the screen's whited out to disguise a jump cut - after the flash Chandler's noticeably further back than he was before.