I have a pet peeve regarding the display of time.
Although my schedule is far from “like clockwork”, I tend to be an early riser. I’ve been known to participate in f2f meetings that start at half past six in the morning. I also sometimes work until two in the morning. So when someone says “talk to you at seven thirty”, that’s an ambiguous time. I’m no fan of ambiguity when it comes to something so specific as a time. Sometimes I know that the person is not a morning type, so they don’t mean seven thirty AM. Often though, I have no such context.
Many years ago I had an important meeting get screwed up as a result of this. Someone who was in fact an early riser scheduled the meeting for ‘seven’. I was there in the morning. No dice. I couldn’t do the evening. End of story. Since then, I have been using the twenty-four hour clock notation for documenting time. Seven in the morning is 0700 and seven in the evening is 1900. No ambiguity. No screwed up meetings.
The twelve hour clock’s time has passed. The US and Canada and Australia are anomalies and minorities and we ought to get with the program.