Here in England, there's a very significant cultural divide between North and South. One of the key symbols of that cultural divide is whether people thank the bus driver when disembarking. In London, thanking the driver would make you a bit of a weirdo; in Newcastle, not thanking the driver would make you dreadfully antisocial.
I imagine that there's a huge difference in this respect between a McDonalds in Manhattan and one in a small town.