Kisses Sweeter Than Wine - S3-E5
Continuity mistake: When Niles first takes out a hanky to put to his bleeding nose, it is folded in a square and remains that way for a couple of shots. Soon, though, without Niles changing it, the hanky becomes rectangular.
Kisses Sweeter Than Wine - S3-E5
Continuity mistake: When Frasier comes out of the bathroom, he has shaved without water, and has at least 4 bits of tissue with blood on them stuck to his face. Within 5 minutes he is greeting his guests at the door and his face is completely smooth with no sign of a cut or scrape.
Kisses Sweeter Than Wine - S3-E5
Continuity mistake: Frasier comes home from work and Joe is explaining what work needs to be done. The shot changes as the phone rings and suddenly Frasier's coat, which had been over his left arm, is over his right arm.
Chosen answer: The turkey's stuffing.