One morning, a few weeks back, I made eye contact with someone who was obviously having a rough morning. I knew I shouldn't engage but I also didn't want to ignore them, so I gave a quick good morning. They promptly responded, "fuck your morning."
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.
"What do you mean?" he said. "Do you wish me a good morning, or mean that it is a good morning whether I want it or not; or that you feel good this morning; or that it is a morning to be good on?"