Continuity mistake: In "Attack of the 50 Foot Eyesores", the executive goes to the piano and you can see a penholder on his desk. But the camera angle changes to behind the piano in the next shot, the penholder has moved position and there are now more items on the desk.
Continuity mistake: In "Time and Punishment", the family stand up to see Flanders on the television set in front of them at the breakfast table and you can see there is nothing behind Marge on the table, but when the camera angle changes in the next shot, a glass has suddenly appeared.
Continuity mistake: In "Time and Punishment", when Homer returns after sitting on a fish, he enters the kitchen and you can see the table is completely clear. But when Bart and Lisa (as giants) attempt to kill their father, we cut to Homer and there are plates with food and glasses on the table.