For me: tech trees

I don't necessarily hate tech trees, some games work great with them, but a lot of games make them overly complicated or don't explain to you well what each choice does or mean, or don't allow respecs giving you tons of stress, or the entire system is confusing or have too many choices and you have to do one for every single character or the game doesn't even need a tech tree because the game should just be a simple platformer (looking at you Mirror's Edge Catalyst)

I'm also a player that generally just likes to make use of what they're given, I don't mind RPGs that don't let me customize my character to the point that every character can use any spell or class or whatever, I'm fine with "this is what you got, figure out how to best use it"