Mind reading
You’re extra sensitive to reading the minds of non-human animals and can’t turn it off. All the time. Forever.
spoiler
When you read someone’s mind you involuntarily blurt out everything you read.
Flying
Extreme fear of heights
The ability to get my DnD group to have a sensible, routine schedule, with no cancelations.
You DM becomes your literal dungeon master. You’re literally chained naked in a basement, forced to play endless games of DND.
The side effect is intended to be bad.
Super speed of course!!
I like to imagine that this is what it’s actually like for The Flash, or Quicksilver or another speedster:
Sure, you can move super fast, but to do that, your thinking also has to speed up to handle that fast movement. So, it’s more like everything else in the universe slows down except you. Now, it’s still an amazing power, but think about those times when The Flash uses his super speed to build a brick wall nearly instantly, or to read every book in the library in the blink of an eye.
To you, building that brick wall takes what feels like a week. You’re running at what feels like 30 km/h to get a handful of bricks. It feels like it takes you about 20 minutes to get to the place with the bricks. You run them back to the place you’re building the wall, you put them into the wall. Then you run another 20 minutes to get the next load of bricks. While you’re doing this boring wall building, you can’t chat with anybody, you can’t listen to a podcast, you’re just stuck doing manual labour for what feels like a week without any distractions or entertainment.
If you speed-read every book in a library, that feels like it takes a month. Hopefully you like reading dry reference books, or whatever it is you’re reading, because that’s all you get to do for however long it takes. Someone watching you might see you flipping through the pages in fractions of a second. But, to you, it still feels like it takes 2 minutes or so per page, and that’s if the material isn’t difficult to understand.
Maybe super speed needs to come with super autism so that you get really engaged in these tasks and don’t mind sinking what feels like days, weeks or months into one monotonous thing.
I can shit at will
You can’t piss at will.
Poor will, never getting that number 1
ability to make people say/do what you want them to
You never experience true trust and understanding ever again and you will never see the genuine version of anyone you interact with, only the mentally enslaved shells of people.
that’s a curse not a side effect
It’s really just something that would come with the territory, like the character of Kilgrave.