"I'm only now realizing my interest in some things I could have spent more time learning when younger"
Same here.
When you're young, nothing has consequence - so I don't think you can put together A + B = some outcome that matters!
Also - I think that every time you learn something, you get a new 'lego block' that you can use. When you're young, you don't have many blocks, so you can't do much.
But as you get older, you have so many blocks (+ money to spend) and you can do so many more things ... it's kind of incentive to learn.
The ability to see a larger project through I think would be a great thing to learn.
I wish that in school - some projects were worked on that took months to complete, and that the kids had to be involved in the planning. I think that would start teaching kids about 'time horizons' and how complex things get done over time.