I was accustomed to needing to be on time for school, for business meetings, etc. One day, not too long after I moved East, a neighbor invited me over for some do. I arrived 15 minutes after the stated arrival time time, trying to be considerate in case they were running a bit late. I was the first guest to arrive and no, they weren’t quite ready. It was a while before the others arrived. There did seem to be quite a few unstated rules that I, a Californian, was unfamiliar with.