Continuity mistake: At the beginning of the show, when Niles and Frasier are in Cafe Nervosa, the man behind them has a paperback book which is open with all the pages fanned out, and then it is lying flat, then fanned out again, and so on. It is not a case of him changing the book naturally, as the positions of other things in the shots change slightly as well.
Continuity mistake: Frasier and Daphne are on the elevator; Daphne has a bag of groceries. In some shots several inches of a loaf of French bread is seen, but when she gets off the elevator the bag is sealed up with no bread visible. The bread becomes visible again in later shots as they talk at the door and go into the apartment.
Continuity mistake: Daphne has the bag of groceries on the floor between the coffee table and the couch - when Stephanie leaves the apartment the loaf of bread is sticking out on the left side but when Marty comes into the living room, the bread is now on the other side of the bag and leaning to the right.
Continuity mistake: Sherry is about to tell Frasier and his date a joke - Marty and she have their arms around each other - the first shot shows her large orange purse is over her shoulder (between them) and behind her but the next shot shows it still between them, but in front of her - simply impossible to have changed its position so quickly.
Continuity mistake: When Martin and Shelly are having a fight, Frasier puts a small bag down, which is yellow on one side and has a logo on the other. He puts it down with the yellow side facing us, and for a several shots it stays like that. However, when Martin is talking about "things that bugged me," you see the bag has inexplicably rotated so the logo is now facing us.David Mercier