Something you’re just good at with minimal effort and/or you learned much more quickly than average.
For me, it’s paper snowflakes. My brain just seems to effortlessly figure out what cuts to make to the paper wedge to make it turn out exactly how I want it. Largely useless, but good fun and was a much-needed ego boost when I was a kid :]
My ex-wife was a medical nightmare, so I got really used to be around ambulances, ERs, etc. As a result of that, I’m calm in (some) emergencies. I’m the guy on the phone calmly explaining the situation to 911 while I watch a pool of blood slowly creep towards my feet.
Also, I can splice bezier curves together seamlessly, while typing in the x,y coordinates by hand.