Deliberate mistake: When the chickens are first shown, one of them is upside down.
Deliberate mistake: After Barney buys the car from Mrs. Lesh, he and Andy are standing at the steps as he tells her not to look back at the car, and the next shot of Andy and Barney at the front door is the same shot from a few moments prior, but it's been flipped so they would be looking in the opposite direction. (00:09:30)
Boys in the Band / Hex Games - S2-E2
Deliberate mistake: When AJ and Chester show Timmy "The Timmy Tuck", AJ says it has a 1400 degree turn. The diagram shows 140°.
Deliberate mistake: Every time there is a scene on the beach, the background is so fake - the waves never move.
Land of Hold/Penny Henny - S2-E17
Deliberate mistake: When Garfield brings Jon to the broken TV, the scene's animation is still unrendered. (00:01:04)
Deliberate mistake: While Bobby's parakeet is flying around downstairs, before the bird settles down on the TV set there are two closeups of Bobby which are flipped shots, note the furniture and Bobby's PJs. (00:07:00)
The Anniversary Present - S2-E1
Deliberate mistake: In this episode Lucy is trying to get Ricky to notice that their anniversary is on Monday the 19th by showing him a large calendar with the 19th circled. However, when they are in California and they celebrate their anniversary and Ricky asks for information to be wired to him, the telegram tells him that their anniversary is on the seventh.
The Wedding - S4-E3
Deliberate mistake: In the scene where the tow truck guy crashes the car window, notice the glass goes in the car. Later the glass is there, but Josh sits in the car without being cut by it.
Deliberate mistake: In fight scenes, the Yellow Ranger's stature matches that of a male (and not Trini). This is because in the Japanese version of the show, the Yellow Ranger was played by a man.
Open the Door Witchcraft - S1-E28
Deliberate mistake: Sam and Darrin are "trapped" in the garage; however, you can see a side door.
Honey, I Shrunk the Rangers: Part 1 - S1-E16
Deliberate mistake: Monkey Bulk & Skull are driving Lt. Stone's car. From inside shots of the car, Monkey Bulk's head doesn't go above the headrest. From outside shots, we can see the guy who was driving the car - his head is way above the headrest, and he's wearing a frizzy fur costume (Monkey Bulk & Skull's fur is very fine).
Deliberate mistake: When Sixsix impacts with the ground due to Greymatter sabotaging his jet pack, the furrow he ploughs into the ground is already present when he skips across the ground.
Smack in the Middle (2) - S1-E2
Deliberate mistake: Ignoring that its very unlikely all of Jill St. John's copious red hair would fit under a wig that passes for Robin's hair, it's impossible that it would emerge from under that wig looking as full and perfectly styled as it does when she's in the Batcave.
Deliberate mistake: When Mary gets to the school where she is going to be teaching, all the children are standing outside wearing shoes. However when they come in to the school they are barefoot. I have a feeling this was done to show how poor the community she was teaching in was supposed to be, but it looked like too cold and rainy of a day to let the actors be outside barefoot.
Deliberate mistake: When one of the yellow fire trucks moves away from the burning Thompson Tower, the back of the truck is set alight by the flames.
Deliberate mistake: In the very first episode, the kids are fighting and arguing all throughout the house. Claire then asks Cliff, "Why did we have 4 kids?", referring to Denise, Theo, Rudy, and Vanessa. In all of the following episodes, they actually have 5 kids. I guess they decided to add Sandra (the oldest Huxtable) later down the road.
Deliberate mistake: Jesse is looking for his keys and thinks Michelle took them. Near the end, Joey comes home and finds the keys in the door, hands them to Jesse, who puts them in his pocket. A few seconds later Danny comes home, takes Michelle into the kitchen. Joey and Jesse exchange a couple lines and go into the kitchen, where Michelle is sitting in a booster chair at the table. The 3 guys chat for a few minutes, then Jesse is going to leave, but can't find his keys again. It turns out Michelle has them. But how did Michelle get them? She was in the booster seat the entire time Jesse was in the kitchen and Jesse never went to that end of the room, so there's no way she could have gotten them.
Deliberate mistake: When Jill turns off the light to Randy's room, she uses the same switch that Al used to activate the reverse laundry chute.
The Ghost Next Door (1) - S4-E3
Deliberate mistake: Right before rising to check out who was calling her name, Hannah sets her laptop, which she was using to write a letter, on the bedspread. The computer screen is shown to be blank, meaning, 1. she switched it off, which she didn't, or 2. it was out of order, which doesn't make sense since she was using it seconds before. (00:02:10)
Pipe Dreams - S3-E11
Deliberate mistake: When Zack brings an oil covered Becky to the biology teacher, you can see that it's a fake duck.