1. Hogwarts
A magical wizard school sounds like a great place to spend your childhood, but Hogwarts isn't all it's cracked up to be, and going to school there would probably suck.
The Wizarding World in general is kept a secret from muggles because muggles would kill wizards if they found them, so there's always that kind of pressure which could make any wizard anxious.
The sorting system is hugely biased, with Gryffindor and Ravenclaw being seen as the best houses, Slytherin consistently demonized by the other houses and administrators, and Hufflepuff being shoved to the background. You're SOL if you're in the half of the student population not in the Main Character House(s).
Also, the school is such a maze that if you have any sort of trouble with directions for any reason, you can expect to get hopelessly lost on a regular basis.
And to add icing to the cake, the school does not seem to teach basic education, focusing instead on magic, making it difficult for wizards to make a living in the muggle world or develop important basic thinking skills.
2. Wonderland
This world may seem bright and colorful, with eccentric characters and a playing card/tea party aesthetic that is visually pleasing, but it's actually a nightmarish hellscape.
The rules of the world make no sense, are not explained, and you could be executed by the queen for not following them. Very few people are interested in helping you. Things could change in weird ways in an instant.
Actually, it sounds a lot like being an adult in general.
3. My Hero Academia
In the world of My Hero Academia, 80% of the population has a quirk, which isn't exactly a superpower and more like a mutation that usually gives the wielder unique abilities. That's an important distinction, because a lot of quirks would not actually be all that great to have.
Some quirks just cause weird physical mutations that aren't very useful for much of anything, and some get the wielder into more trouble than they're worth. The ones that are powerful or useful are rare, and there is a clear hierarchy especially when it comes to employment.
And God forbid you're in the 20% of the population that is quirkless, like Deku is at the beginning of the series. Being quirkless in this world is the same as being disabled in our world, with all the ostracization and lack of accommodation that comes with it.
4. Marvel/DC Universe
In fact, the existence of superheroes would suck in general. This is especially true in the Marvel and DC universe where superpowered individuals frequently have godlike powers that can level entire cities effortlessly.
The thing is, not all these beings are heroes. There are just as many villains in these universes, and they terrorize the population on a daily basis. They also have a bad habit of getting out of any prison they're thrown into.
Living in a world with superheroes, if you're not superpowered yourself, would be living in a state of constant anxiety. Or we'd end up in a world like Watchmen where everything is a dystopian nightmare for other reasons.
5. Minecraft
The Minecraft world is secretly a post-apocalyptic wasteland. There are no humans anywhere except for villagers, and they're only interested in trading. They also regularly get wiped out by zombies, which emerge in hordes every night along with skeleton archers. There are abandoned mineshafts that seem to be created by creatures much like you.
What happened in this world and why are you the only survivor? Even if you knew the answers, it wouldn't change the fact that you are the only human left alive. No amount of wheat farming and wolf taming will replace human connection. If you lived in the Minecraft world, you would go insane from loneliness after a few weeks.
6. Steven Universe
If you're a gem, you may be functionally immortal and able to change your appearance at will along with other useful abilities. But you would still be under the rule of Homeworld and forced into a caste system, defined by your gem type and nothing else. Or if you rebelled and became a Crystal Gem, you would be either shattered or in hiding and preparing for Homeworld to come again.
If you're a human, you live in a world where beings that are basically goddesses live among us, and they don't have the same moral code as humans. They can and will destroy entire landscapes in their battles and some of them try to bleed the planet dry to create more of their own kind.
