Other mistake: When Sideshow Bob leaves Selma to watch MacGyver, the room opposite is 350. Later when he is being taken away by the police there is a room 44. It's unlikely these two numbers would be on the same floor.
Other mistake: Right before Homer and Bart head to the concert, Homer has the high-pitched ringing in his ears while Marge is talking. Then just as Homer says, "I hear you. C'mon, boy," note Selma's and Patty's skin over their scoop necklines are not colored in properly, it's the same color as their dresses. (00:01:45)
Other mistake: At the concert when Bart throws the Frisbee into the dude sat next to him, the crowd in the background are all missing their eyes. (00:03:50)
Brother Can You Spare Two Dimes? - S3-E24
Other mistake: On the DVD, when Homer is sitting on the Spinemelter, he says at one point "I've tried to fill it with family, religion, community service, but those were dead ends. This card is the answer." However the subtitles say "I've tried to fill it with family, religion, but those things were dead ends. This card is the answer", leaving "community service" out.
Suggested correction: It is very common to shorten the subtitles so viewers don't have to read much.
Other mistake: When Lisa checks Marge's resume, she reads it and turns it over. But there is no text on the back as there should be. (00:06:30)
Other mistake: When Homer pretends to read the newspaper, the back page is very noticeably blank and missing any print. (00:08:00)
Other mistake: When Moe is running to the Simpsons' house there is a shot of him running past the moon. When running back to the bar, the same shot is used but is simply flipped. Note the house and rocks. (00:18:20)
Other mistake: When Homer is crossing the rickety bridge in the snow plow there is no snow on the planks even though he is in a blizzard and the storm couldn't have just started because the path he just came from was covered in snow. (00:18:55)
Homer's Triple Bypass - S4-E11
Other mistake: In the beginning of the episode when Chief Wiggum orders a battering ram through The Front door of a house, Reverend Lovejoy opens the door and questions what they are doing. Chief Wiggum says "isn't this 742 Evergreen Terrace?" to which Lovejoy replies that it's the house next door. In the next shot, you see Snake pulling out of the garage and speeding away. Everybody knows that 742 Evergreen Terrace is, in fact, the Simpson residence. (00:02:40)
Marge vs. the Monorail - S4-E12
Other mistake: When Homer crashes his car, he just disappears when it hits the tree. (00:01:50)
Marge vs. the Monorail - S4-E12
Other mistake: Lanley's desk in his trailer suddenly gets brighter even though none of the lights in the trailer were turned on. (00:12:50)
I Love Lisa - S4-E15
Other mistake: When Lisa and Ralph are swinging at the end, they are swinging outside the frame, but the swing is tied at the top of the inside of the frame.
Krusty Gets Kancelled - S4-E22
Other mistake: When the Red Hot Chili Peppers are performing on Krusty's TV special, bassist Flea is playing a standard electric guitar.
Homer's Barbershop Quartet - S5-E1
Other mistake: When the Be Sharps are singing at the Statue of Liberty, in some shots the stars in the sky are black.
Homer's Barbershop Quartet - S5-E1
Other mistake: When Bart and Lisa are looking at records, there is a picture of Homer. He had hair at the time the record was made, and the hat he's wearing isn't big enough to cover it, but there's none visible as there should be.
Tree House of Horror IV: The Simpson's Halloween Special IV - S5-E5
Other mistake: When Bart says the picture of the school bus is actually called The Ghoul Bus, Lisa points out the name tag says The School Bus. If you closely at the name tag, you can see nothing is written on it.
Other mistake: When Homer and Chief Wiggum fall into the waste, in the second shot, the cliff edge looks very weird. It seems to be transparent with Ruth's car floating in mid-air, and there is a big curved wall that doesn't have ground at the top.
Other mistake: When Ned and Homer's raft is going fast, Ned decides to go on the left side of the gorge, so he paddles on the left side, which causes a raft to turn to the right, which 1, means the raft moved to the left, which is impossible, and 2, he wanted to go to the left, but paddled like he wanted the raft to turn right.
Other mistake: In the scene where the Simpsons are viewing the path of the Corvair's Re-entry, the blip representing the spaceship crosses the entire US from North-West to South-East in about three seconds. This is really impossible, even for something going as fast as a spaceship on re-entry would be.
Other mistake: When somebody throws a cola can at Homer, the can never hits the ground.