Continuity mistake: This is a mistake within a mistake: Niles and Frazier are trying to get the wrapped presents out of F.'s apartment and replace them with others, to play a trick on their dad. They are getting completely mixed up, and presents are being taken out and then returned by mistake, mostly by Frasier. At one point Niles has a pile of gifts which he puts down on the table behind the couch - the shot shows him holding them, but the next shot shows a completely different pile of presents, even though it is supposed to be the same pile. Frasier picks this pile up. It soon changes again in the next shots.
Continuity mistake: Frasier and Niles are looking at the report the private detective gave them on Sherry - Niles is holding one sheet apart from the others but as he says "it does bode well for Dad", the papers are all together again, with no real time for this to occur.
Continuity mistake: While Frasier and Marty are in the kitchen arguing about Sherry, his can of beer moves from the right side of the counter quite a distance over to the left of the dishes he broke. The sugar bowl and jam pot also change positions during the same shots.
Continuity mistake: Frasier is holding a plate of food in the kitchen, but after Roz comes in with the exploded cherries jubilee all over her, the food on his plate has changed completely. It could not have been affected by the cherries jubilee explosion as he had his back to the door when that happened.
Continuity mistake: When Niles goes to take off his pants he looks over at Eddie who is sitting on the right side of the armchair. The next shot shows Eddie getting out of the chair and onto the footstool - however, he is climbing out of the left side and he had no time to shift position. (00:01:55)
Continuity mistake: Near the end of the show, Dr. Nora's mother is chasing Nora through the corridors of KACL, behind the windows of Frasier and Roz's booth. We can see them go by, from window to window. The shot then cuts to Frasier, looking horrified, and we see Nora's mother run by a couple of windows again - even though this could not possibly have happened in real time.
Continuity mistake: When Frasier and Niles are in the restaurant, Niles is under the influence of medication. He lays his head down on his arm just as one of the geniuses arrives and greets them. In the next shot, his head is lying right on the table, with no time for him to have switched positions.
Continuity mistake: When Marty, Niles, and Frazier return from the taping of the Antiques Road Show, Marty hangs up his blue windbreaker and then Frazier hangs up his gray raincoat, obscuring Marty's coat. But throughout the scene, all we see is Marty's blue jacket - where did the raincoat go?
Continuity mistake: During the opening scene, Niles is on the phone to his chef, and behind him, on a table, are two champagne glasses (beside the phone base)and 3 candles. He hangs up the phone, moves away and 2 of the candles and the glasses have disappeared, and the phone has been pushed further over. He sits on the couch, then goes to get the ironing board - when he sets it up we see the glasses and candles are back.
Continuity mistake: In the opening scene, Niles goes to pour sugar on his spoon and the top of the sugar dispenser comes off and disappears - it looks like it goes into his lap. We don't see the top again until after the teenager says, "Aren't you going to yell at them?" and suddenly it is in plain view, on the right of the table.
Continuity mistake: Marty gives Niles a mug which says "World's Greatest Psychiatrist." He puts it down on the coffee table with the lettering facing the camera. He then leaves with Daphne and a few shots later, we can see the mug again, but it is turned around and we see the blank side. When Frasier leaves the apartment, it's back in its original position. Nobody ever touched it.
Continuity mistake: As Frasier tells Bulldog that he shouldn't feel threatened by Clint, we can see the edge of a clipboard moving on the bottom right screen, where Roz would be. However, in the shot before that, Roz had pretended to punch Bulldog - she had nothing in her hand and wouldn't have had time to pick anything up.
Plot hole: During the scene when Frasier is in Cassandra's hotel room, he phones Roz and puts his phone back in his jacket pocket. He hangs his jacket on the back of the chair and eventually gets into bed with Cassandra, who soon falls asleep. He talks to her but she doesn't answer. We then hear him phoning Roz - but there was no time for him to get out of bed and get the phone - and no sounds of him doing this.