When the encyclopedia dealer offers Joey one book for $50, and Joey takes the "V" edition, he clearly has the $50 note in his hands as he flicks through the book. When the shot changes to the dealer one second later, he is tucking the note into his pocket.
When Chandler is handcuffed to the file cabinet and saying he wants his Freedom, he and Rachel start off in a tug of war with his pants. During his Freedom speech, he has one hand cuffed to the file cabinet, with the other hand he's pointing at Rachel demanding his freedom. Rachel too has her hands empty.
When the camera cuts to a shot of both and Chandler says "Why won't you hear me?" and opens the door to ask Sophie for help, he's once again holding the pants, which he then drops to open the door.
When the camera cuts to a shot of both and Chandler says "Why won't you hear me?" and opens the door to ask Sophie for help, he's once again holding the pants, which he then drops to open the door.
Joanna exits the bathroom in a towel, says hi to Rachel, goes to Chandler's room and closes the door behind her. In the shot where Chandler promises Rachel he will end the relationship, you can see in the background that the door is open again. This is explained in the extended edition of the episode, in which Joanna comes out of Chandler's apartment, leaves the door open and tells Rachel she's late to work if she intends to get Joanna a bagel. After this occurs, Rachel asks Chandler to promise her to end things with Joanna.
When Phoebe hears the oven timer ring, she says that "the ruined quiches are ready." But as she opens the oven door you can see the quiches are already out and on top of the oven. However, in an earlier scene, there were four trays of quiches. Monica, the perfectionist, would have cooked one tray at a time in the middle of the oven to ensure they were all cooked evenly. There are only three trays on the counter when Phoebe pulls the fourth out of the oven.
When the salesperson is showing Joey the encyclopedia he supposedly points to a painting by Van Gogh but the page he points to only has text. Then when he looks up "vulcanized rubber," he stays near the front instead of looking it up at the back.
When Chandler is cuffed to the chair in Joanna's office, he could simply have picked up the chair in order to get the keys to the handcuffs.