I will admit it, I give a right-handed off-the-bars normal person wave to the Greenway park workers in their jeep/golf cart or blowing machine. It's traditional, I've seen them just about every morning for years and a lot of the regulars do it. Which is likely my fault for starting it up. The poor guys probably have to wave to bikes every minute now. But just their job or not, I very much appreciate them keeping the path cleared every morning, and pulling sticks and branches and who knows what else off.
But other cyclists, joggers, drivers after I leave the path, it seems mostly pointless. Some mornings there's a "good morning" to just about everyone, sometimes not. You really can't read anything into whether a cyclist waves or not.