I lived in Los Angeles for 7ish years. Great place, but it was mind boggling to me how often people were late (as a first generation Canadian with British parents). To the point where I'd show up to _job interviews_ 10 minutes early and the recruiter would tell me, "Oh! We usually start the interview 15 minutes later than we tell candidates because everyone is late." Even more surprising to me was amount of people who would _say_ they would come to an event and simply not show up last minute without even a text.
I live in Taipei now and that simply doesn't happen. My theory for the difference is in LA it's culturally acceptable to be late because people can blame the traffic for everything. Also, LA is a lot more transitive, with people moving in and out all the time.
Taipei is on an island, there's a lot less people who move in and out compared to LA so it's a lot more likely you'll bump into the same person multiple times. Also, everyone takes the metro, which is always on time, so you have to take responsibility for being late. (You can't just blame "traffic").