Continuity mistake: In the episode 'TOW Phoebe Runs' when Rachel runs into the horse at the end there is a shot of the horse looking round at her, when the shot changes angle to show Rachel picking herself up you can see that the horse is still looking straight ahead.
Continuity mistake: When Phoebe and Ross are talking about Ross buying his sheets at the flea market, Phoebe says, "Ross, come on, you gotta loosen the purse strings a little" with her hands by her side. The camera cuts and her hands are now out in front of her.
Other mistake: In this episode when Joey and Ross are filling out the form for Ross's hand in the ER, Ross states that his birthday is October 18th. However in Season 1 - The One With George Stephanopoulos, when Joey and Chandler are pretending to take Ross to the hockey game for his birthday he says that his birthday was 7 months ago. He then asks if today is October 20th.
Continuity mistake: When the Snippy Guy is pointing out couples to go on the platforms next, he points to one couple with his left hand, while holding a clipboard in his right hand. In the very next shot he points to the next couple, but this time with his right hand while holding the clipboard in his left.
Character mistake: In the early years, the gang are talking about their pets dying and their parents saying they sent them to a farm and Ross thinks that actually exists. He said that they sent their dog Chee Chee there and HE could run about chasing animals. Then in TOI Massapequa, Monica is preparing her speech and she tells Chandler about Chee Chee and said SHE died when Monica was in college, and when Parker asks whose dog it is, Monica says HE's my old dog. Then during her speech, Monica says HER and Nana are gone.