Continuity mistake: When Opie surprises Andy by telling him that he wants to take piano lessons with Clara, he heads to the piano to play what he already knows, and when Opie plays Chopsticks on the piano he's wearing a different shirt.
Continuity mistake: Wilma opens the bedroom door to find Fred covered in flour, but in the next shot the bedroom door has vanished while Fred stands in the doorway.
Continuity mistake: In all other episodes of this season, Officer Dan has blonde hair. This one episode, Officer Dan has gray hair and his face looks completely different from other episodes.