Hehe! Yeah, it's a real thing. More common than you might think, too. Supposedly, hyperacusis affects something like 10%-15% of the population, so the chances you've run across somebody who suffers from it are pretty good. I'd wager there are those who don't even know they have it, thinking what they hear is normal. I know I was quite surprised as a child to find out my eyesight was as bad as it is. I just didn't know any better.