The Aristocats' entire plot hinges on the fact that Edgar apparently believes cats literally have nine lives. There is also that fact that the Disney Encyclopedia writer, John Grant, points out that had Edgar obeyed the wishes of the will, he would have had a guaranteed job taking care of Madame's "heirs" until he almost certainly outlives them (cats in Real Liferarely live more than 12-15 years) and gets the remainder of the inheritance all for himself.
Even worse is his belief that each cat will live for x years times 9 times number of cats. If each cat lives for ten years per life, they will live for ninety years, there are four cats so that would be 360 years... completely ignoring several basic facts (Duchess is older than her kittens and so would live a shorter period after Madame's death, the cats are alive at the same time and not consecutively, cats don't even HAVE nine lives).
Not to mention, the lawyer and Madame are both completely crazy and it probably isn't legal to leave property to cats. It could be left in trust, with Edgar in charge of the actual spending, so there is nothing to stop him living the high-life as long as he keeps buying cat food.
Things for Amanda Waller in Batman: Assault on Arkham would've been a lot easier if she'd merely bribed a guard to kill the Riddler instead of sending the Suicide Squad in. It would've be easier, less messy, and given her reason for doing so was to keep how to defuse the nanobombs she uses to keep the Squad in line a secret, they wouldn't have learned if she didn't send them in. Addtionally, given the Riddler isn't the only criminal mastermind, she also could've tried coming up with another countermeasure. Alas, she sent the Squad in, people got killed, the Riddler blabbed about his knowledge, most of the Squad had their bombs defused by him, the Joker escaped and started a riot, and the Riddler (the very person Waller wanted dead in the first place) escaped during the riot.
The last third of Gumby: The Movie falls into this. Someone even suggests calling the police after the blockheads have Gumby and the band kidnapped, but the agent says "No time for that". While it thankfully turns out well with the blockheads tied up and the robot substitutes deactivated...They literally just leave the blockheads tied up...in their lab...and within a meter of the controls.
The so-called "Love Experts" are anything but. First, their solution to Elsa's magic problem is to remove Anna's memory of it. They then proceed to frighten Elsa with their warning of fear, but not clarifying what they meant, leading to her parents shutting her in the castle to protect her and to allow her to control her powers, ironically causing her control on her powers. Later in the movie, the trolls try to marry off Kristoff and Anna, despite one of the morals of the movie being that you shouldn't marry too impulsively. Finally, when the elder troll comes up with the idea of the act of true love, it's another troll who suggests the whole kiss thing. Thankfully it was a beneficial mistake as had they known better, Anna would not have had the opportunity to save her sister.
Anna's relationship with Hans is an intentional and lampshaded one. First she impusively tries to marry him when they barely knew each other and then leaves Hans in charge of the entire castle. This allows Hans to manipulate her and almost win. Both Elsa and Kristoff find this to be incredibly bizarre.
The LEGO Movie has an in-universe example: The popular Show Within a ShowWhere Are My Pants? has exactly one joke: A man can't find his pants. For every episode.When Wyldstyle hijacks the show's set to make a broadcast, she throws a pair of pants at the actor, declaring "Found your pants! The series is over!"
Meet the Robinsons. The whole plot could have been easily avoided in the first place if Wilbur took a second to listen to his mother and check that he locked the garage door behind him. Or if Cornelius Robinson was the tiniest bit more careful about how he handled his rejected inventions. Or if Goob raised the issue of Lewis keeping him up at night either to his roommate or even his caregiver in the first ten minutes of the movie instead of ignoring it until it became a serious issue that resulted in bruising. This movie seems to take the Idiot Plot to nearly self-conscious levels given its primary Running Gag consists of both the villain and the hero making poor decisions that backfired and then subsequently told off by their allies that their poor decision not only didn't work but got them in even more trouble. In the end the movie is resolved by having Lewis claim the whole movie never happened. While a neat way to clean up everything, this also results in a severe Broken Aesop where no one had to take responsibility for or learn from their idiotic actions in a movie where the message is supposed to be "Learn from your mistakes". Interestingly, the movie even parodies itself in this regard in an alternate ending. In this ending, Lewis takes Goob along with him in the time machine to the day when Goob fell asleep during his game. Goob shouts at his past self to wake up and his past self does so, then proceeds to catch the ball and win the game. Future Goob then contemplates how this was all he would've had to do all along and all his other plans were unnecessary.
Norm of the North would have been non-existent if the developer didn't try to sell homes in the arctic. Or if Norm, after hearing how the ad campaign is dead unless they find someone who looks just like him, goes with them to stop him! Why is never explained, except with a fight-them-when-their-guard-is-down logic. Somehow NO ONE actually does anything, with Mr Greene being the one with the idiotic schemes, and almost everyone is useless. Early in the movie Mr Greene runs around NYC with a rifle TO SHOOT NORM IN A CROWDED RESTAURANT! Not only should he not have done that, but everyone likes him for it, and it somehow raises his approval ratings. That should've happened at the end where they tricked him, getting him fired. Why did they make him do that? Why would you like someone you didn't like before when they'd gone postal? Why buy a house in the Arctic? Everything is stupid. Why are the lemmings the only ones who aren't complete idiots? They can't even speak.
Scooby-Doo and the Cyber Chase is guilty of this. Someone created the virus. No one knows who. They get zapped into their friend's game, which is based on them. Can't they just get pulled back out? Of course not! Turns out the "geniuses" that made the special laser and game didn't think to make an emergency escape program. That's not all. The virus, for some reason, likes to make baseball references, constantly. Does the gang figure out who made the virus straight away? No. They make it to the final level and face off with the virus. The reveal of this "mystery" is that Bill the baseball fan was the one who created the virus. Nice job, gang. That was a tough one.
Though the team do pick up on the baseball references and it's not like they were in a position to tell anyone. The real idiot is Bill for injecting so much of himself into his virus that it could easily be traced back to him.
Right after Springfield is sealed in the dome, Professor Frink reveals that he has a laser drill that can break through it, but it's outside the dome. The trapped Springfield residents could have dug a tunnel under the dome, retrieved the drill, and started breaking through. Not a single person in town figured this out, even AFTER the Simpsons escaped the dome via the sinkhole in their back yard.
The residents spend most of the episode oblivious to the possibility that their problems could be solved with an old-fashioned town hole digging (Willie asks himself why he didn't think of that), and it is a guest star (Sting) who is the best digger. Springfieldianites just are not very smart, especially when it comes to digging holes, since moreover in another episode they dig themselves into a hole and their plan for digging their way out is to "Dig up, stupid". The real idiot plot in this movie is Homer dumping waste into the lake after he was warned by his non-idiot daughter that this would be the death of everyone and everything he loved. But then again, it's quite common for Simpsons plots to exist because Homer willingly crippled his IQ with a crayon and did something stupid. Lampshaded in a later episode wherein Mr. Burns decides to cover the town in a dome, only to been told it happened already. Then Carl points out that they could've dug their way out the last time.
Tangled Ever After: The whole plot of the short happens because the Princess and her fiance give their wedding rings to a horse to hold on a cushion it keeps in its mouth, during the ceremony. As cool as said horse is and as much as they've been through with him in the original movie, isn't that asking for trouble? Cue the majority of the short being the horse and his chameleon buddy chasing after the wedding rings all throughout the city, to get them back in time before the bishop ends his speech. They succeed in that, but then the horse accidentally catapults the wedding cake away...
Thumbelina does ask the bird to take her home several times. The bird genuinely thinks that it's more important to abandon her in favor of finding Cornelius. Yeah.
We're Back! A Dinosaur's Story: A scientist from the future goes back in time and collects dinosaurs, force evolves their brains so they're just smart enough to be able to speak and reason on a fourth grade level (except poor Dweeb, who's basically left intellectually-impaired), brings them to modern day New York and then just drops them off in the city with very vague instructions of finding a fellow scientist without any training or understanding of how modern life functions. The entire city mistakes them for balloons, until one girl points out they're not, just because they happen to be marching with the Thanksgiving Day parade, never mind the fact that they are dancing and singing. Then a good chunk of the plot revolves around the dinos stumbling into trouble, being chased by the authorities and then trying to rescue two kids who stupidly signed a contract with an obviously creepy old circus owner. The time traveler comes back to save everything, but after all the madness has happened, not before. If anybody in the movie put more than three seconds of thought into their actions, it would be a pretty short story.
The heroes and NPCs of Wreck-It Ralph are well aware that (a) their villains are only doing a job and not actually evil and (b) a main character running out on their game is a very, very bad thing. Doesn't stop them treating their bad guys like dirt and then acting all surprised and dismayed when one of them finally snaps and abandons his game to try and make a better life for himself.