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.
Having been to quite a few countries in Europe, I’ve heard more about UK tourists than USA tourists, although the few UK tourists I met were friendly.
The USA is a massive country with hundreds of millions of people. There are rude people, but there are also friendly people. It just depends on where you are (and unfortunately in some places who you are). Having been to Seattle, people were generally friendly, but you can’t blame the barista for wanting to get through the line that goes out the door and two blocks down the road.