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.
The opposite happened to me in Japan. For the love of God I can’t do an asian squat and there was only this old style squat toilet there. On top of that I really had to go because I had a bit of a diarrhea situation going on. I had no idea which one was the front and which was the back of the toilet. I figured if I try it I will just shit on my pants, so I had to completely remove them. Then I awkwardly lowered myself down no some kind of a weird squat, holding on to the walls of the stall for life, sweating like hell and bam, some of it went on the toilet.
I was relieved that I didn’t shit myself but mortified how to clean up my mess. In the end I was able to clean it with some water and I was lucky that it was in the night (at a cheap hostel) and nobody came in why all of this was happening.
Hadn’t thought about the trickiness the other way. Before I visit I will definitely spend some time googling how to poop in Japan.
Most bathrooms in Japan have either western style toilets or a choice of both, especially in urban areas. But better to not be caught unawares.