Other mistake: When Ross is at Monica's party getting Mr. Green's glasses and cigarettes he bumps into Mrs. Green and ends up having to come up with an alibi for the glasses and cigarettes. He then puts the glasses on, puts a cigarette in his mouth and says 'In fact I'm gonna go out into the hallway and fire up this bad boy'. At this point he walks past Rachel but he stops still as if frozen mid-step just before the shot cuts to him walking out into the hallway.
Factual error: Joey and Chandler are supposedly crossing the George Washington Bridge but the exterior background viewed from inside the car is very obviously a repeat reel of another bridge, and their conversation goes on for far too long for the actual crossing. And the cutaway shot after Chandler is kicked out of the car shows an aerial view of the Brooklyn Bridge.
Continuity mistake: In the scene where Ross and Carol are talking and Carol says that all he needs is to find a woman who likes men, a woman comes across the room walking in high heels. The shot is wrong because we see her up until she's half the way through the table, and the next shot shows her four steps back.
Continuity mistake: At the beginning of the episode, Phoebe gives Monica a push on her rollerskates and then we cut to Gunther giving Rachel a mug of cocoa. At this point, Monica is about to crash into Rachel, but as the angle changes we see Phoebe giving Monica a push for a second time.