Continuity mistake: Frasier is having a glass of sherry, sitting on his couch, talking to Niles and Martin. As Marty says "let's go have dinner", Frasier throws his hands up - in real life he would have still had the sherry in his hands. There was no time for him to have put it down.
Continuity mistake: When Niles, Roz, Marty, and Daphne are in the living room confessing something shameful, Martin says, "Every time I watch 'The Sound of Music,' I cry." As the shot changes, we see that his hand goes from his arm rest to his lap and his beer can goes from being on one side of the remote to the other.
Continuity mistake: When Frasier is reading from the psychiatric journal that contains Niles' letter, at one point he is holding it in both hands by the front cover - the shot changes and he has one hand on the front cover and one hand on the back cover, without time to switch naturally.
Continuity mistake: In the scene where Frasier and Niles are talking in Cafe Nervosa, the position of Niles hands and arms change a couple of times. At one point, while Frasier talks about the young woman he has met, Niles folds his arms in front of him but in the next shot to Frasier, we can see Niles fingers laced together - and then the shot returns to Niles with folded arms. They stay this way until another shot where he says "You were in a mall?" and his hands are suddenly on the table and one is lying over the other.
Continuity mistake: When Daphne goes to Niles's place to see him, she sits down on the couch and slides her purse behind her. A couple of shots later Niles gets up and now we can see her purse on the couch to her left. At no time did she make any movements that could explain its change of position.
Continuity mistake: Throughout the Christmas parade we can see that the headphone/microphone is on the left side of Frasier's head. During the first break just after one of the crew members is telling Mary that her improv is really good he tells Frasier to lighten up. Just after he says this you can see that the headphone/microphone is now on the right side of Frasier.Lummie
Continuity mistake: At the beginning of the show, Frasier is sitting with Martin and Niles in Cafe Nervosa telling them about the radio play. As Marty says "we were a simple people", Frasier manages to open his briefcase, take out the script, put it on the table, and put his briefcase back on the floor and be sitting still - all in about 3 seconds. This just wouldn't be possible in real time.