At the risk of sounding a bit dumb, I shorted my motherboard with a USB A, it felt like I got it right, and pushed it in, at which point it shutdown. Fortunately there didn't seem to be any permanent damage
Happens to the best of us. I also had a bit of a scare like that recently. The only thing worse than a non-reversible connector is one that breaks (or fries your device) when you insert it the wrong way...