Continuity mistake: In the last scene of this part of the show, where Frasier is trying to figure out if Cassandra is romantically interested in him - he removes his outer clothes and stands in front of her closet. We see his clothes change position several times. Sometimes they are on the back of the chair, sometimes they are on the floor. His shoes also change places. In fact, the shoes appear to move on their own at one point and are pulled tidily to one side.
Continuity mistake: Frazier meets his date (Cassandra) in the restaurant - she places her purse down, and it constantly moves around in different positions while they talk. Sometimes it's to her right, sometimes to her left, and one it is lying on the table with her hand over it.
Continuity mistake: At the end of the scene Niles opens the apartment door and waves his arm; the little white cloth is thrown and lands under him as he faints and hits the floor. Eddie heads for the couch and the shot shows the white cloth on the floor in the hall outside the apartment door. (00:11:20)
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: When Niles is engaged in his ironing fiasco, Eddie is watching his every move. When Niles heads to the kitchen to get spot remover, Eddie is sitting on the footstool. The next shot shows Eddie turned to watch Niles - but he is now in the chair; it is not just a tricky angle, as he actually lays his chin on the back of the chair. There was no time for Eddie to jump from the footstool to the chair.
Continuity mistake: When Niles goes to take off his pants he looks over at Eddie who is sitting on the right side of the armchair. The next shot shows Eddie getting out of the chair and onto the footstool - however, he is climbing out of the left side and he had no time to shift position. (00:01:55)
Continuity mistake: During the opening scene, Niles is on the phone to his chef, and behind him, on a table, are two champagne glasses (beside the phone base)and 3 candles. He hangs up the phone, moves away and 2 of the candles and the glasses have disappeared, and the phone has been pushed further over. He sits on the couch, then goes to get the ironing board - when he sets it up we see the glasses and candles are back.
Plot hole: During the scene when Frasier is in Cassandra's hotel room, he phones Roz and puts his phone back in his jacket pocket. He hangs his jacket on the back of the chair and eventually gets into bed with Cassandra, who soon falls asleep. He talks to her but she doesn't answer. We then hear him phoning Roz - but there was no time for him to get out of bed and get the phone - and no sounds of him doing this.