My superpowers seem to be messing things up, misinterpreting what people say, and being in the way (seriously, it's uncanny how often I try to move out of the way only to end up being exactly where someone wants to be).
I've never been asked that question, but I have seen things like "I have autism. What's your superpower?" on a T-shirt or something. If that's my superpower, I want a refund. I seem to have all the downsides without really any good sides (well, I used to have the stereotypical Aspie memory when I was a kid, but I seem to have permanently lost that due to depression). I don't even have any obsessive interests that could be of any use, even without a related skill. I honestly have no idea how I'd answer that question - I'd probably end up just stammering a bit until the person gave up on trying to get an intelligible response from me and left.
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Yet in my new wildness and freedom I almost welcome the bitterness of alienage. For although nepenthe has calmed me, I know always that I am an outsider; a stranger in this century and among those who are still men.
-H. P. Lovecraft, "The Outsider"