I like to stick with a simple "hello" so I don't have to keep track of time (e.g. during meetings across timezones or even when I'm so scatterbrained that day that I lose track of local time) and it's also less presumptuous.
People have accepted that 'morning' is my standard greeting regardless of the time of day. It's even become a thing everyone says within my close friend group.
As a teenager I'd sometimes just randomly sprinkle in complete nonsense as a greeting, like 'wtf is oatmeal', or 'I speak for the trees', and hardly anyone noticed
Same here! I was already prone to saying "Morning!" anytime, as is... but after working nights for years, it has become permanent. I stopped trying to figure out what time of day it is when greeting people, so it's always morning lol
But I rarely say, "Have a good morning". It's normally just "Have a good day"