Oddish take on this thing for me, perhaps -- from relatively early on, until about 2003: I lived in London -- where in those times, one entered and exited the bus, via the rear: interaction with the driver, not a feature. On moving to the Birmingham area, I discovered the custom there of -- with "in and out" at the front, past the driver -- when getting out, thanking the driver (via one's preferred form of words). It struck me then -- to some extent, still does -- as a bit weird (why thank the chap for just doing his job?); but at the same time: rather sweet, and benign. From fairly early-on in Brum: I acquired the habit of, on "exiting", saying "thank you" to the driver -- except in stressful or concentration-requiring situations, when it may with me, go by the board.
I have to wonder whether there's a more than tiny minority of curmudgeonly drivers, whose sentiment is: "I get sick to death of being thanked twenty thousand times a day -- I'm just doing my bloody job -- can't people just shut the **** up and simply get off the vehicle?"