Continuity mistake: Niles says on Daphne's wedding day that he told her he loved her on his 3 day anniversary, making Daphne's wedding his 4 day anniversary. At Nervosa, Mel says it's their 4 day anniversary, when at this point one more night has passed and it's now 5 days since they married.
Continuity mistake: Frasier is in Donny's office, and Donny is holding a little wedding cake groom. He covers the groom with his hands while he's talking, but when Frasier says, "Daphne realizes you went to great expense," the little bridegroom is visible again, even though in real time it couldn't have happened.
Continuity mistake: At his "reception" Niles has his arm around Mel and says, "I didn't even have to check her teeth" to a member of the horsey set - and the shot then shows Mel and Nils standing apart, even though there was no time for them to have done this.
Continuity mistake: When Niles and Daphne are on the roof having their picnic, Niles tries Daphne's peanut brittle but when she turns away he throws it off the roof, and lays the plate down on the blanket. When Daphne turns back and asks him what happened to the candy, we see him holding the plate again, even though he had no time to pick it up.
Continuity mistake: When Daphne and Niles are on the roof having their picnic, the basket behind them is opened from the center and on the inside on the left are two champagne glasses. A couple of shots later and the glasses are now on the right side, even though no one touched the basket.
Audio problem: Frasier is standing in his living room talking to Niles. We hear a knocking or tapping. As Frasier is expecting his date, Miranda, this might make sense, but they do not seem to hear it and make no move towards the door. A short time later the doorbell rings and Frasier's date arrives.
Continuity mistake: When Niles and Daphne are on the couch talking about the meteor shower, she has his hand on his left knee and he is covering it with both of his hands. After he says "two horrible wrongs", his right hand is suddenly on his right knee, with no time for natural switch.
Continuity mistake: The butler and Frasier are discussing the new president of the opera board and Ferguson pours Marty a cup of coffee. In the next shot, over Marty's shoulder, we see he already has the cup in his hand, although there was no time for this to happen naturally.
Continuity mistake: Roz is at Frasier's soirée joking with Mr. Worth about selling him some giftwrap. Just before she says "everything but my bracelets", her drink and hat switch from her right hand to her left and her canapé from her left to her right. In the next shot they've switched back again.