@Terxbor I generally use what the other person starts with, so I sometimes wish people good morning at five in the afternoon.
@BatElite My preference is depends on whether the conversation is real-time (or close to it) or not, as well as if I know the other person's time zone. If it's real-time, I prefer what is appropriate for their zone. If real-time returns false, or time zone returns null, then I use what is appropriate for the time at my location.
@BatElite
Good morning, cutie. (Well, it's late, late night in my internal reckoning, 2:46 AM PST, though I'd still use the word "morning" anyway.)