The Excel question in GQ reminds me I used to excel at Excel. Back in the 90s I had a job which involved a lot of spreadsheet work, and I knew every short cut, keyboard command and whatnot. There were complex calculators which had required two to three days labor and I wrote macros to automate it all. Got it down to about 30 minutes.
Fun stuff.
Now I rarely use it and it’s all forgotten.
Doing things one handed, or doing things with my arm. Since my left hand is not very good, I’ve learned arms and elbows can do a lot more than people use them for. I’m very fast at work because I hold the bag open with my bad left hand, scanning and bagging the items in one motion with my right hand. When people tell me “You’re really fast,” I say “I bet you don’t know my secret” and explain my left hand injury.
I’ve gotten a lot of dropped jaws on that!
I’m told by many I’m able to do amazing spot-on imitations of others, often after only having heard once: The speech patterns, cadences, inflections, vocal tones ( high to deep, whiny to gravelly ). Some have said I’m so good they wonder if I imitate them to others.
I tell them it’s in their interests to be on good terms with me. 
I guess I’ll be the first to volunteer a big dumb meathead thing: powerlifting.
If you want something extremely heavy moved for one rep, I’m your man.
I’m good enough for my weight class to be regionally competitive - to put that into perspective, in my medium sized gym, the only person on the leaderboard who competes with me for the #1 spot in absolute amount of weight moved is 4-5 weight classes above me, i.e. 80-100lbs heavier in bodyweight.
There’s just something about it - when I’m going for a max either in the gym or in competition, there’s just this ineffable feeling of “I was born to do this” as I’m psyching myself up for the lift.
Picking up something extremely heavy and putting it down again seems like a pretty pointless thing to be proud of, but I’ll take what I can get at this point. 