I was thinking about that when I was dropping my 6 year old off at some hobbies earlier - it’s pretty much expected to have learned how to ride a bicycle before starting school, and it massively expands the area you can go to by yourself. When she went to school by bicycle she can easily make a detour via a shop to spend some pocket money before coming home, while by foot that’d be rather time consuming.
Quite a lot of friends from outside of Europe either can’t ride a bicycle, or were learning it as adult after moving here, though.
edit: the high number of replies mentioning “swimming” made me realize that I had that filed as a basic skill pretty much everybody has - probably due to swimming lessons being a mandatory part of school education here.
Not really stories, just not-good experiences. Had a couple/few moments where someone disagreed with the whole hard thing. I was going along a ledge near water recently and people assumed I had the same floatation magic as everyone else when I was thrust in and even after they (except for someone’s dog) saw what amounted to thrashing. So it works both ways.
That sucks pretty hard.
If you want to, they do offer swimming courses also for adults, at least over here.
It might be worth the investment.