The One With The Giant Poking Device - S3-E8
Factual error: The "very long poking device" that the friends fashion out of chopsticks would never actually work. It has vulnerable points every half-foot or so (the length of the chopsticks) and after a certain point would just break or sag under its own weight at one of the vulnerable points.
The One Where Monica and Richard Are Just Friends - S3-E13
Factual error: Joey refers to several of his favorite parts of The Shining in 'code', including "all blank and no blank makes blank a blank blank, " which obviously refers to the "all work and no play makes Jack a dull boy" scene from the movie. However, that scene (and the one where Danny sees the two "blanks" in the hallway) is not found in the book; only in the movie. (00:13:55)
Suggested correction: I know they're talking about the book, but doesn't it actually make sense for Joey to be referencing the movie, even though the conversation is about the book? Considering the character, I don't think that's off at all. He's read the book, but he's obviously seen the movie, too.
Later in that scene, Ross references The Shining as a book Joey loves that stars Jack Nicholson. Therefore, it's safe to assume that Joey has seen the movie and the audience could infer that he may confuse the two often enough for Ross to reference it that way. This might just be another Joey mistake (which he has many) vs a factual error of the show.
The One With The Hypnosis Tape - S3-E18
Factual error: When Pete takes Monica to Rome for the date this would have been impossible as Rome is 6 hours ahead of New York and at least 4/5 hours travel time, assuming they went by Concorde (double that otherwise). They would have had to have left New York early in the morning to make dinner for 8/9 pm in Rome.
The One With The Screamer - S3-E22
Factual error: Rachel's date yells at the theater patrons who are in the gang's seats; one of them has D13, and he screams "you're surrounded by even numbers, does that give you some clue?" However, the establishing shot shows they're at the Lucille Lortel Theater, which has odd-numbered seats on the left - the side they're sitting on. It is also a relatively small house and doesn't have a D13; the outermost seat in that row is D9. (00:04:50 - 00:05:30)
Factual error: When the gang all see the beach house for the first time, it's covered in a layer of sand, which is supposedly left over from a recent flood. Well, if there really had been a flood, there would have been mold on the walls and debris or junk from the outside, and the sand wouldn't have been nice and clean and dry; it would have been moldy. And there would've been a pattern, likely on the walls, of where the water rose up to and where it receded. Not only that, but how did it get in? All of the doors and windows are intact. (00:04:40)
Factual error: When Bonnie shaves her head, Rachel is supposed to have given her the razors (according to Bonnie.) Nope - the kind of razors needed to do that kind of close shave are a very particular kind, and Rachel isn't going to have them unless she also shaves her own head. It also wouldn't make any sense for Bonnie to have used her own razors; she's not going to carry them around with her unless she's planning to use them.
Suggested correction: Considering Bonnie always used to shave her head, it's not beyond the bounds of possibility that she just kept a razor on her in case she wanted to do it again. She's an impulsive type of person, after all.