Continuity mistake: If you look closely at the couch in the first scene ("A Valentine for Niles") it is not the same couch used during the rest of the run of Frasier - it looks brand new and it doesn't quite have the same texture or look. It makes sense, as Niles sets fire to the couch at the end of the scene.
Continuity mistake: Frasier and Marty are sitting in their living room talking about Frasier's problems with women. Marty has his fork poised above a plate with a slice of cake on it. The next shot shows the fork on the plate, next to the cake. Marty would not have had time to put the fork down in the split-second in between.
Continuity mistake: Martin is drinking a glass of milk which is between his arm and a bowl of chips. Suddenly the milk is sitting well to the left, even though he didn't touch it. (00:14:35)
The Show Where Diane Comes Back - S3-E14
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: Frasier and Niles are in the kitchen at the cabin. Niles picks up his mug to take a sip, but in the next shot his mug is still on the table.
The Great Crane Robbery - S8-E4
Continuity mistake: When Todd is in Frasier's booth talking to Kenny, Roz, and Frasier, sometimes the door to Roz's booth is open and sometimes it is closed, without anyone going near it.
Continuity mistake: When Frasier is saying goodbye to Mr. Rugly, he knocks over Mr. Rugly's coffee mug with his umbrella. The mug is tipped off the table but in the next shot Mr. Rugly grabs it - but in real time, by this point the mug would have already hit the floor.
Duke's, We Hardly Knew You - S2-E5
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: During the closing credits, Roz is sitting at in Cafe Nervosa with her little black purse on the table. While she is preparing her coffee and flirting across the room at a guy, her purse disappears from the table for the rest of the scene.
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: Marty, Daphne, and Sherry are all shouting at each other around the dining room table - there are two chairs between Martin and Daphne but when the shot changes to Frasier coming in, now Marty and Daphne have no chairs between them.
Continuity mistake: While Daphne and Sherry are arguing, Marty says, "See, I'm regretting that one already", and his rolled up exercise mat, sitting on the table, rotates about 45 degrees.
Continuity mistake: Frasier is serving tea to Niles in the first scene and sometimes the tray is sitting straight on the corner and sometimes it is askew. The teapot changes position on the tray as well.
Three Dates and a Breakup (2) - S4-E20
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.
To Kill a Talking Bird - S4-E14
Continuity mistake: At the beginning of the show the spoon in the custard dish on Martin's table shifts from side to the other from shot to shot.
Continuity mistake: Daphne and Martin are at KACL with Roz and Frasier, talking about flu shots. Then Marty starts talking about McGinty's and suddenly there is a clipboard on the console that wasn't there before, and wasn't put there during their conversation.
Roz, a Loan - S6-E9
Continuity mistake: Martin was holding a little blue bag on Eddie's head to comfort him; when he gets up he tosses it on the coffee table, but when the shot changes it is sitting several inches away from its original spot.
Roz's Turn - S4-E17
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.
Answer: In the last episode, they explained that Tossed Salad and Scrambled Eggs is a metaphor for the mixed-up people to whom Frasier dispenses his radio psychiatric advice.