For me, it’s hereditary magic. I can deal with random people not being able to use a setting’s magic (though I’d prefer magic to be accessible to everyone), but I hate the weird vibes that scream eugenics to me.
Naruto
My Hero Academia
Harry Potter
Just to name a few, take something as cool as powers and magic and turn them into things where you end up with characters incentivized to breed the perfect people.
Like I get people like the idea of going all Gregor Mendel with fire dad and ice mom to make a cool fire and ice kid, but then it’s just gross and I don’t know. It makes me think back to when I was younger. How so much of your life could be decided before you were born. I don’t know, it didn’t make it fun playing pretend.
What about you? What magic system tropes did you hate?
Not a fan of when there’s one magic system and seemingly everyone in the world is on the same page about it. Even in science you have conflicting theories to explain certain things - with magic, where half the shit you do is seemingly random and the results you see are based on vibes, practically every person wielding it should have a completely different understanding of what they’re doing and why it works. That should be the reason why it’s so hard to pass from teacher to student - I could teach you to do the same things I do, and speak the same incantations, but that doesn’t mean it will work for you the way it does for me, because it’s magic and it’s inherently illogical.