I'm doing it, always have. A lot of other colleuges never do it.

I would argue that this has just nothing to do with poor/rich or where you work.

Perhaps its just random how your work environment or your collegues are.

one thing that stood out to me when i was in Southampton in the UK was that every passenger on the bus would say some form of "thank you" on their way off the bus.

So, sometimes, yeah.