Continuity mistake: The flashback is set in 1993, but all the characters look the way they did three years later. Most noticeably, Frasier's hair is short and not long and wavy like in the first season. Daphne's appearance has changed quite a bit too.
Plot hole: Once the gang have arrived in Canada, Daphne is scared stiff of getting caught outside the USA. Marty explains they will just "smuggle" her back and Frasier and Niles are outraged at such deception. But to get into Canada, all of them would have had to declare their residence, birthplace, and reason for coming in. To get Daphne in in the first place, they must have lied. She would have had to show her passport as an alien. The Americans would have been allowed in without their passports, per diplomatic agreements. So the outrage of the boys makes no sense.
Continuity mistake: In the doctors office, the doctor wheels Ann out and leaves the X-Ray he just put up of her leg. Later in the scene after Martin and Frasier have their conversation, Ann comes back into the room on crutches. When she does, the X-ray that was on the board has disappeared and never returns through the rest of the scene.
Continuity mistake: During the opening credits, Bulldog is on the phonein the hall at KACL and he throws a tennis ball at Frasier, who stumbles around trying to catch it. During the scene we see an extra behind Bulldog go into one of the rooms - but we see her do it again just a split second later - and the second time she has a paper under her arm, where she had nothing the first time.
Continuity mistake: During the scene when Marty and Daphne are in the car going to the shoe store, she stops at a red light, as does the black car on her left. During the shots that follow, the car on the left, although always black, is a different car in different shots.
Continuity mistake: When Niles is drunk in Frasier's appartment, he puts a six-pack of beer cans on the table by Martin's chair. The pack has changed position on the table later on when Frasier is talking about empowerment, without anyone touching it.
00:09:15 - 00:10:35David Mercier
Continuity mistake: During the opening credits, Frasier, Martin, and Daphne are sitting at the table talking about getting older. At one point Martin says "when people reach our stage in life" and his left hand is holding his coffee cup. But as the camera cuts to Frasier we can see Martin's hand in the left corner of the screen, up in the air, without the cup. The next shot shows it back on the table, holding the cup again. All this happens too quickly for the changes in real time.
Continuity mistake: During the closing credits, when Niles goes to Frasier's with some licorice, Marty is lying on the couch, sick. At first his cane handle is facing the fireplace, but when the shot changes, it has moved about 45 degrees towards the window.When he gets off the couch, the handle is facing the fireplace again.
Continuity mistake: Soon after Abbie has arrived at Frasier's, Daphne says to Niles, "It's cute when you do it," and he has his hand on her shoulder. In the next shot, his hands are in his lap and she is taking a sip from her glass, with no time for a natural change.
Continuity mistake: Frasier and Niles are in the hospital waiting area, sitting on the couch. Frasier says, "We must remember," and his hands are outstretched, one on each knee. The next shot shows his hands clasped together, with no time for the change.