Continuity mistake: When Homer hands over the key to Mayor Quimbey, the mayor points out the teeth marks on it. But in the next shot when Homer says he thought there was chocolate inside, the bite marks are gone. (00:16:30)
Continuity mistake: When Flanders walks up to the door, there is nothing next to the door, but in the next shot after Homer has thrown garbage onto him, there is an egg box next to the door.
Plot hole: A little ways into the episode, when Milhouse kisses Homer, he says that was the first kiss in his whole life. However, we see him kissing Samantha Stanky in the episode "Bart's Friend Falls in Love," in Season Three.
Continuity mistake: When Moe gets bitten by the snake in the cash register, he has bites all over his hand. But in the next shot when Barney sets him on fire, all the bite marks are gone.
Much Apu About Nothing - S7-E23
Continuity mistake: When Homer,Barney and Moe are in Moe's making signs Moe says 'But they ain't bothered...' and leans on the pool table with his elbow.In the next shot he is leaning on it with his hand.
Continuity mistake: At the beginning, when Homer and Marge are discussing the pregnancy test, the pattern on the bathroom walls, disappears and reappears, and in one shot, there's pattern on one side of the wall, but not on the other.
Continuity mistake: When the doctor asks him if he has a moment and Mr.Burns looks at his watch but by the next scene it is gone.
Continuity mistake: Bart's guitar is lefthanded. So when the righthanded Otto plays it on the bus, the guitar is flipped over, with the little speaker on the top. But when Otto is playing it later in the garage, it is a normal righthanded guitar, with the little speaker on the bottom.
Continuity mistake: Rodd's hair is black when him and Todd are in bed singing. It can't be because it's dark, because Todd's hair is unchanged. (00:15:10)
Continuity mistake: When Lisa is on the television talking about her tax rise, we see inside Moe's tavern. Look at where Lenny and Carl are sitting because they have moved 3 or 4 seats down when we go back to them later on. And there is no reason why they would they move like that.
I, (Annoyed Grunt)-bot - S15-E9
Continuity mistake: When the family are eating dinner after the robot fight, their water glasses change position between shots. (00:12:40)
I, (Annoyed Grunt)-bot - S15-E9
Deliberate mistake: When the giant gold robot picks up the robot containing Homer and shakes him, Maggie suddenly pops up from nowhere and bounces around along with Homer.
The Old Man and the C Student - S10-E20
Continuity mistake: The springs on Homer's hat change size when Agnes answers the door to him.
Radio Bart - S3-E13
Audio problem: When Homer talks to Marge about Bart's present, the same footage was taken from 'Saturdays of Thunder,' because you can see that Homer's mouth doesn't move right. (00:02:40)
Springfield Connection - S6-E23
Continuity mistake: When the police pull up outside the station they park three cars in front of the entrance,in front of the steps. In the next shot they are apart on the road, then when Marge walks by them they are in a line to the side of the steps.
Like Father, Like Klown - S3-E6
Continuity mistake: When Miss Pennycandy barges in on Krusty's 'Sex Chat,' she leaves the door open. It remains closed for the rest of the scene. (00:04:15)
Continuity mistake: While Homer is sleeping, his head is facing the 'Core temperature' indicater. When he wakes up, he is in a different position. (00:04:25)
Continuity mistake: When Bart finds out that Homer took the police badge out of the cereal box, it changes from brown to pink. The food inside the box also changes to pink. (00:01:10)
Moaning Lisa - S1-E6
Continuity mistake: When Marge is driving Lisa to school, in one shot you can see that her necklace is red. Then in the next shot it is white. It then changes back to red and stays that way.
Continuity mistake: In the cinema, it is clear that the people attending the movie keep on changing. For example, For a few shots, you can see that Krabappel and Skinner are sitting in The Front row, but the next time you see those seats, they have been replaced by Lenny and Carl and Krabappel and Skinner aren't in sight.