Continuity mistake: Frasier is in the kitchen and gets the sugar out to sprinkle over the profiteroles. As he starts shaking we get a wider shot and we see there is sugar all over the stove top, pastries, plate, and counter - way more than there should be for the amount of shaking going on.
Continuity mistake: Fairly early in the show Frasier has his dad call the police station to ask about a female officer Frasier is interested in. Marty asks for her name, hangs up, and gives Frasier a lot of information about Maureen that he couldn't have possibly learned in that short a time.
Continuity mistake: About two thirds of the way through the show, Marty and Frasier are talking in the living room. Marty is sitting in his chair with a glass of milk. One shot shows him with both hands on his milk, and then he puts his left hand on the arm of the chair. In the next shot his hands are around his glass of milk again.
Continuity mistake: Niles runs into the kitchen where he finds Frasier cleaning the oven. As Frasier stands up, one of the cuffs on his rubber gloves has been turned over, and the other hasn't. A couple of shots later they are both neatly folded over. As Frasier leaves the kitchen, they are back to the first position. At no time did he adjust them.
Continuity mistake: Marty and Sherry are looking at old photos to use at Marty's birthday party - we can see one in Sherry's hand that has noticeable brown marks down the back, as though it had been glued in an album. The next shot shows Marty passing this one to her, even though in the shot before it was in her hand. When Sherry passes the picture over to Niles and Frasier, in the shot when they get it, it's not the same photo, as it is clean on the back.
Continuity mistake: In Cafe Nervosa, after Niles has taken off all his clothes, Frasier wraps him up in a couple of Cafe Nervosa aprons and Roz picks up Niles' clothes from the floor. In one shot, we see his tie towards the top of the pile in Roz' arms, and in another it is swinging free at the bottom of the pile. The clothes change position in her arms from shot to shot. In one shot the boxers are still on the table, with a newspaper. In a subsequent shot, Roz has the boxers. When Niles is being taken outside, the table nearest the door has only a cup on it. In the next shot, we see the newspaper on the table again.
Continuity mistake: As Frasier pushes Sherry towards the balcony, we can see a gold decorative thing on her green purse. In previous shots to this, the gold piece didn't show, because the other side of her purse was facing out. At no time did she turn the purse around.
Continuity mistake: In the same scene where Bebe's hands change position from shot to shot, and Frasier is warning Roz about Bebe having no reflection, Frasier's hands on Roz's arms change as well. In some shots his hands are on her upper arms, in others they are on her lower arms.
Continuity mistake: When Frasier and Marty are talking about going to Ronee's cabin, Ronee is sitting on the right side of the couch with nothing behind her. In the next shot, she gets up and we can see a light brown overcoat. This coat disappears again in the next shot, as Frasier answers the door and Niles comes in, carrying the very same overcoat which he places on the right side of the couch, where Ronee had been sitting.
Continuity mistake: During the opening credits of the show, Frasier and Roz are in Cafe Nervosa. Frasier has a fabric shopping bag, and in some shots you can see the leaves of one vegetable and in other shots you can see the leaves of two vegetables. These leaves are quite large and distinctively different.