Continuity mistake: There are several errors in the plant's parking lot: 1, in the overhead shot of the plant, we see Homer drive in, and there are parking barriers on the road. These disappear in the next shot. 2, As he drives in, there are at least eleven parking spaces on the right side of him. Carl takes up one spot, and in the next shot there are about 3 parking spaces left. 3, When he parks, we see several cars behind him, but in the shot before that, no cars are visible, not even parking spaces, and 4, when both Homer and Carl drive in, we see orange lines on the road, which weren't visible in any other part of the scene.
Continuity mistake: When Homer gets turned into a jack-in-the-box, we don't hear the chair he was just holding crash onto the floor. Bart doesn't make it vanish, as we see it on the floor when Homer is turned into a jack-in-the-box.
Continuity mistake: When Homer sees Marge and Moe near the end, the coffee table changes size between shots. It's large when Moe sits on the couch.It's smaller when there's a shot of Homer and long again when the high shot shows Homer walking out (when his rags are stuck on it)
Continuity mistake: In 'The Shinning,' Homer is chasing his family with an axe. They are hiding behind a curtain, and then they run outside, away from Homer, opening only one of the double doors. In the following overhead shot of them running through the snow, both doors are now open.
Continuity mistake: When Homer is in Lisa's classroom and imitates a farting sound, there is a sink at the back of the classroom and nobody is using it. However in the wide shot, there are suddenly two people by the sink. When the shot is back to Homer, nobody is by it.