Continuity mistake: Toward the end of the episode, Rachel is back in Ross' apartment, trying to mend the ornament she broke when she was in there earlier. Ross comes in unexpectedly and she tosses the broken pieces into the lightshade, leaving the glue on the side table. In subsequent shots, the glue goes from lying on its side, to standing up, a number of times. (00:16:00)
Continuity mistake: In the episode where Rachel goes to tell Ross she loves him (in England) she leaves her room with a brown sleeveless vest and a cardigan over her shoulders. The cardigan then disappears in all other shots until after Phoebe says "he's in love with the British chippy". Her leather jacket also goes from being in her hands to over her arm. (00:19:30)
Continuity mistake: When Charlie and Benjamin are at the restaurant, Benjamin says "I can't believe you chose this restaurant. You remember that night?" To which Charlie replies "I can't believe they let us back in here." However in "The One With The Fertility Test" Charlie has never been to New York before.
Continuity mistake: While Monica's preparing her shake in the blender she asks Rachel about the anniversary dinner, and when Rachel tells her that she and Ross broke up, Monica throws the blender lid and it flies over the counter, but in the next shot the lid is back in Monica's hand, and then it vanishes again. (00:01:10)
Continuity mistake: On the actual prom video tape, it only takes Ross a mere 12-13 seconds to run up the stairs, completely change outfits into his Dad's tux, and reappear ready-to-go on the stairway. This is impossibly fast. Also, it is not possible that the prom video tape was stopped and re-started during this time, which could account for the short duration. The reason is because Ross's mom was the one filming at this point. It turns out that she has no idea how to stop the video recorder. Thus, the video tape was one continuous recording, and we are expected to believe that Ross could change outfits within 12 seconds. (00:21:25)
Continuity mistake: When Rachel is talking to Joshua near the drinks table at the party, he is holding a blue cup in his left hand and nothing in his right (this is most obvious when she's offering him a cherry). When she begins to choke, he raises his empty right hand to pat her on the back, then when she walks away there is suddenly a bottle in his raised hand. The shot changes, and his hand is again empty and he reaches down to the table and picks up the same bottle. (00:08:30)
Continuity mistake: When Chandler mentions how long Alexandra has been massaging Monica, he is holding a bowl,and he walks away with it. But when Monica says to Phoebe, "you can understand why this would be weird for me", the bowl is on the table. (00:05:20 - 00:06:00)
Continuity mistake: When Monica says, "I just recently got out of a serious relationship," she is holding her glass in her left hand. The camera cuts to Pete and the glass is now in her right hand. It then switches back to her left hand in the next wide shot.