This may not be a video game skill in the traditional sense, but one thing I'd like to be able to do in real life that a video game character can do is craft and transmute objects using a Horadric cube like in Diablo 2.
There are many ways to use this ability that I can think of.
The most immediate use of this ability for me would be to put my desktop and laptop into the Horadric cube to craft a new, upgraded gaming laptop--to play more GOG games, of course. Doing this would consolidate my two computer systems into a single upgraded system and save me the trouble of having to sell the two old computers, since I'm always looking to get rid of things that take up space as space is a precious commodity in my house. This would also prevent me from contributing to all the e-waste that results from old electronics that end up landfills and would therefore be good for the environment.
Another important use of crafting and transmutation using a Horadric cube would be to solve the basic problem of hunger at home when there are only odds and ends left in the fridge. Put in various leftovers in the Horadric cube, hit transmute, and, BOOM, you have delicious pierogi, lasagne, or T-bone steak.
Other useful applications of this crafting ability, though stretching it a bit, would be for upcycling furniture, and recycling used necessities into new, unused versions. For example, I could throw in my old couch with some old wine stains along with a discolored rug into the Horadric cube and transmute and out would come a brand spanking new couch and carpet. The size of the furniture would be limited by the size of the Horadric cube--unless the Horadric cube happened to be like Mary Poppins's bottomless bag. Also, putting in used A4 paper, old newspapers, and dated magazines into the Horadric cube and transmuting them could yield a packaged ream of 100 sheets of A4 paper--or a box of 4 or 5 of such reams. The possibilities of this ability would be endless--and great for the environment and for reducing one's carbon footprint. And it would most certainly be fantastic for your wallet! Imagine not having to pay another $1,000+ to upgrade to the next iPhone or Galaxy phone. Just put in your old phone along with the case, protective film, and charger, and boom, you have the next new smartphone with all the new accessories.
While this would go beyond the purview of the original Horadric cube in Diablo 2, if you have an annoying sibling who is getting on your nerves, you can transmogrify him or her into a frog for just a few hours in the Horadric cube. Just don't ask me how you would get your sibling in the cube.
Anyways, that's a video game skill I would like to have in real life: being able to use a Horadric cube (from Diablo 2) to craft and transmute objects into new and better objects.