Continuity mistake: At the beginning when Chandler is talking about two reasons to pick a minister, he counts them using his left hand. However, in the wide shot straight afterward his right hand has two fingers up and his left hand is in his lap.
Visible crew/equipment: In the scene where Monica, Joey, and Phoebe are sat on the couch in the coffee house, (whilst the camera is drifting left) a boom mic at the top of the screen is visible for a short period of time. During this time the mic can be seen moving.
Continuity mistake: When Monica and Chandler enter the apartment arguing about what time they were supposed to meet, Monica has her handbag strap over her right shoulder, and then takes it off. When the shot switches to Phoebe claiming to know what time they said they would meet, the handbag strap is back over Monica's right shoulder, and then she takes it off again.
Other mistake: As the wedding begins, the first bridesmaid, Felicity, walks down the aisle with a man. He is not part of the wedding party but is wearing the same attire as the best men. He is not seen again throughout the wedding. The only two men in the wedding party are Joey and Chandler.
Continuity mistake: When Monica is telling Susan and Carol that Ross used to dress up as a girl, Ross goes over to the table and picks up a drink. When he picks it up it has a cork in it. In the next shot he has the cork already in his hand.
Continuity mistake: When Rachel returns from running after the boy that she told to "shut up", you see Joey picking up a piece of food, sniffing it and making a face and then putting it back on the tray. However in the next shot, without moving, Joey is munching on something - he didn't have anything in his hand before.