Corrected entry: In the last scene of the episode when the friends are sitting on the sofa in Central Perk, Ross has the ice on his forehead because he hit it on the machine in the launderette. At first Rachel is holding it on Ross' head, then in another shot Ross is holding it, then Rachel again, and then in the final shot Ross is holding it. It may be that they did keep switching but it's unlikely and looks more like the scene was filmed twice and the mistake was made when it was edited.
Corrected entry: When Rachel and Ross are pulled over by the Cop on the freeway, the Cop states that Rachel's starsign is Aquarius, based on her driving licence details. However, in series 4, 'The One With Joey's New Girlfriend', she tells Gunther that her birthday is May 5th. That would make her starsign Taurus.
Corrected entry: In this episode, Chandler is speaking to Nina, when they both agree that their processing term, "WENUS" is short for "Weekly Estimated Net Usage Statistics". However, this is inconsistent with the previous episode: Season 1, Episode 15, The One with the Stoned Guy. In that episode, Chandler is speaking to Monica, Ross, Rachel, Joey and Phoebe in Central Perk, when he says that "WENUS" is short for "Weekly Estimated Net Usage Systems".
Corrected entry: There's an impossibility with the view out of the guys' apartment. Take a look at the hallway set: On the left there's the door to their apartment, then a wall, then the stairwell, which runs on the other side of the guys' kitchen/bathroom/living room. Yet when you go inside and see that same wall, it's got windows that show a direct view of outside. Those windows could only show a view of the stairwell.
Corrected entry: In 10-9, The One With The Birth Mother, Erika hands Monica and Chandler a sonagram picture. Would they not see that she is carrying two babies on the sonagram? In the episode where Erika is giving birth, neither she nor Monica nor Chandler know that she is expecting twins.
Corrected entry: When Ross decides he wants in on the lottery, where do his tickets come from? They don't go out to the shop to buy some. It could be argued that he bought some when Phoebe lost the tickets over the balcony, but I think he'd be more pre-occupied on finding the ones that were already lost.