Continuity mistake: After Martin lowers his chair and gets the bag of pretzels it cuts back to Frasier and you can see the bag still on the coffee table. Then it cuts back to Martin and he has the bag. (00:06:16)
Continuity mistake: When Frasier and Martin are yelling at each other about the mess on the carpet, Marty is holding a red plastic oil container. In one shot there is a noticeable dribble of oil on it, but in the shots before and after, it is clean.
Continuity mistake: When we first see Marty on the floor oiling his chair, his cane is lying on the floor with the handle end pointing towards the kitchen. When he picks it up a few shots later, it has turned 180 degrees and the handle is pointing towards the door. At no time did he touch it.
Continuity mistake: When Frasier comes home, just after Marty has sprayed oil on the carpet, the pattern of the spray changes considerably from one shot to the next.
Chosen answer: The turkey's stuffing.