Revealing mistake: When Skinner starts to drive the bus, he says "Off we go". During this shot the sky is a brighter colour when you look out of the bus windows than if you just look outside the bus. (00:12:15)
Revealing mistake: When Bart is swinging on the clothes line into the night, it is obvious that the brightness has been turned down because the sky is the same colour as in the previous shot. If it were night time, then the sky would be a dark purple colour. (00:04:20)
Revealing mistake: On the original DVD version, when Bart says to Lisa "I didn't want you to wreck your life" the screen is cut off on the right side slightly. (00:20:25)
Revealing mistake: While Moe is narrating and perving at a towel-clad Marge, Marge turns to look at herself in the mirror, causing her hair to clip behind part of the wall above the door from her and Homer's bedroom. (00:03:21)
Much Apu About Nothing - S7-E23
Revealing mistake: There are two Ralphs when Willie says: "You want to pick on immigrants?" (00:06:35)
Revealing mistake: When Bart and Lisa enter the H2WHOA! ride, Lisa's eyes disappear for a few seconds. (00:03:30)
Revealing mistake: When Lisa hugs Homer, there's a person next to her with a missing head. (00:21:43)
Revealing mistake: In the scene where the family is in the car, driving home from The Town hall meeting, Homer says "the whole reason we have elected officials is so we don't have to think all the time!" When he says "don't" a second collar appears beneath the right collar of his shirt, and then disappears after he says "time." (00:11:20)
When You Dish Upon a Star - S10-E5
Revealing mistake: At court, as Homer is walking towards Alec Baldwin, Kim Basinger and Ron Howard, Bart is in the background sitting with the rest of the Simpsons, but his head is missing from his body. His head then reappears back on his body after about 2 seconds.
Revealing mistake: When Homer enters the Kwik-E-Mart, the automatic door doesn't fully open, and Homer's left arm goes right through it. (00:03:40)
Revealing mistake: When everyone is cheering for Ned at the neighborhood watch meeting, Apu's hand is yellow.
Revealing mistake: When Homer is on the news talk-show talking to the cat burglar, he puts his hand on his chest and the opening of his shirt appears over his hand.
Revealing mistake: When Homer pushes the soda vending machine next to the candy vending machine, a large scratch appears near the upper right corner of the screen. (00:04:10)
Suggested correction: This is in the questions as well. With the long amount of time the artists have to make an episode it's very hard that something like this would get by them. It's probably the device you watched it on.
One Fish, Two Fish, Blowfish, Blue Fish - S2-E11
Revealing mistake: In the credits it shows Homer eating pork rinds. This is a reused scene from "Moaning Lisa."
Cape Feare - S5-E2
Revealing mistake: After Bob has announced who will be safe, Homer runs into Bart's room and, as the door opens, it goes through a baseball bat on the floor. (00:11:40)
The War of the Simpsons - S2-E20
Revealing mistake: When Maude Flanders says 'Oh, okay' to Homer after he asks for peanuts, the lipstick on her lips briefly flickers and disappears for a few frames. (00:04:56)
Tree House of Horror X - S11-E4
Revealing mistake: When Bart tells Lisa, 'Must have given you super strength,' Bart's arm is not fully coloured red and partially takes the colour of the floor from the background. (00:08:25)
Revealing mistake: When the dog attacks Chief Wiggum, you can see a floating flashlight, a person in the bottom right corner missing an eye, and a cameraman pointing the camera elsewhere instead of at the ground. (00:04:54)
Revealing mistake: When Mr. Burns tastes the burger, his ear briefly turns the colour of his hair. (00:04:25)
