Deliberate mistake: Hank only discovers the tattoo on the back of his head after having his hair shaved off. There is no way, however, he wouldn't have noticed it before this. The tattoo artist had to shave hair off the back of his head before putting on the tattoo. While he might have not realised right away, the pain the following day and the fact that he would have noticed a large part of his hair missing would make it unavoidable.
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: When Johnny is watching the news footage of the Hulk battling Thing, all the footage is merely clips from that portion of the episode, including parts of the battle that were happening before the camera crews even showed up. (00:02:50 - 00:07:20)
Deliberate mistake: At the beginning, Asajj Ventress is wearing an outfit with a long skirt. When she is rescued from her damaged starfighter by the scavengers, the skirt has vanished. This was done because the animators found the skirt too difficult to animate. This is also why she receives a brand new outfit that never had a long skirt later in the episode. (00:08:20)
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)
The Trouble With Trillions - S9-E20
Deliberate mistake: When Homer is being interrogated by the IRS, his package is briefly replaced by a ball of string when the IRS agent sits down in the chair and spins around.
Deliberate mistake: Bandit is knocked over while carrying a basket of laundry. But the Heeler family never wear clothes.
Deliberate mistake: When the world is counting down to the new year, we see people in various countries, Egypt, the USA etc all counting down together. Because of time zone differences this isn't possible. [It is a little joke.] (00:01:35)
Deliberate mistake: At the beginning of the chapter, as the scene switches to the surface fighting on Muunilinst, we see a score of droids blasted before the Republic Army's heavy artillery is brought in. But there are no remains on the droids to be seen after the smoke has cleared, whereas there should be something left.
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.
Yug Ylimaf - S11-E4
Deliberate mistake: The time machine reverting causes everything in life to go backwards. However, although the characters' actions are reversed, their dialogue is always spoken forwards and not backwards. (00:08:00)
What If... Captain Carter Were the First Avenger? - S1-E1
Deliberate mistake: When Peggy and Steve are studying the map where the 107th Army division is held captive, the names on the map are nonsensical names that do not even follow German spelling or standards for place names ("Farfignugen," "Dädtenorth," and "Rosskjhberg," for instance). Most of them are also reused, appearing several times on the same map. This is most likely done deliberately so as to avoid any resemblance to real places, but still looks out of place and illogical. (00:11:27)
You Wish ('Shanghaied') / Gary Takes A Bath - S2-E11
Deliberate mistake: Spongebob gets stuck in the top of a tree as Gary removes the ladder. In previous episodes it's quite clear that he's more than willing to 'fall' as he takes no damage when hitting the ground due to the low fall speed.
Deliberate mistake: When the T-Ship is hit from the blast from the exploding space station, it spins around for a while before it re-stabilizes. Just before it does so, look out of Raven's canopy: the background outside with the stars and even a planet spin as the ship does, whereas realistically it should remain calm and stable.
Deliberate mistake: Season 2, episode 6 "Identity Crisis": When Bizarro starts decaying into the parody form of Superman, his costume goes with it; the blue fades, and even the 'S' insignia changes. Strange that superhero garments change right alongside their wearers when they suffer from an unstable genetic effect. Were the clothes cloned right onto his body, instead of sewn?
There's A Demon Shark In The Froggy Dark - S1-E9
Deliberate mistake: Unless they're super strong, none of Mystery Inc could've thrown an anchor to the top of a cliff.
The Secret of the Unicorn: Part 1 - S1-E3
Deliberate mistake: After Francis Haddock kills Red Rackham, he lights a fuse to the explosives. The fuse that was lit is only a foot long, yet he is somehow able to climb out the ship without anyone noticing, get into a boat and swim all the way to land before it explodes. At a foot long it would have exploded in 10 - 15 seconds, all of that would taken at least 10 minutes. (00:18:45)
The Campground 'Bizarre' Case - S1-E17
Deliberate mistake: The evidence that proves Kindaichi's alibi is the store receipt detailing the time of his purchase. Notice that the year is recorded too, but it reads "20XY." (00:12:40)
Episode XCII - S5-E1
Deliberate mistake: Jack stops his motorbike beside a stream, and Jack's weapon strap crosses over his left shoulder when he walks over to have a drink. The problem is when we see Jack's reflection in the water, his image is not reversed; note the strap is still crossing over Jack's left shoulder. (00:07:20)