I can never remember if AM is After Midnight or After Midday or PM is Post Meridian or Post Midnight, or it's something like that, not to mention when 12:00 is... is it 12:00 or 0:00?. But ah well, I'm lucky to be in a place where we use 24h clocks (but hey, max we see is 23:59:59!) (unless they have arms). Btw, the iOS calendar is (was probably) also pretty "broken" [0]
[0]: https://www.youtube.com/watch?v=ER1a6jgW1Gs