I'd like to go from indoor bouldering to rock climbing, but coordinating with a belayer doesn't seem super interesting and otherwise it's just a matter of expense, gear, and a slight pivot in my leisure time to start going at it.
Otherwise, the skill that seems most out of reach is keeping a job for longer than a year. I'm in a decent spot now, after a year and a half prior of being unemployed, and I feel like this might be my last real shot at a career of any kind. Other people seem to handle it fine, but this is the thing that seems most out of reach. Unlike engineering problems that are made up of abstractions with ways to break them down and piece together systems, keeping a job is as opaque of an abstraction as I'm aware of, that doesn't necessarily depend on a measurable skill or even on anything within one's control. I've never once felt stability or been able to bet on money coming in next year, and if I had the money for a mortgage, I'd be stopped by the knowledge I can't count on an income flow at any time in the future. I'm thankful for what I have and what I've learned nonetheless.