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.
are you saying its transactional then? like a social contract of “it’s my birthday, so I’m paying for my guests food and drink.” You, my guest, have accepted that contract by bringing a gift?
This flies in the face of birthdays I’m used to. There’s no expectation that If I invite someone to my birthday that a) they need to give me a gift (I would never expect that) or b) I’m paying for their food and drink. I guess because that social contract isn’t in place, the idea that someone can come over and say happy birthday isn’t a big deal. It’s just a gathering that happens to be on my birthday.