I think a lot of city people have Agoraphobia, in a city there is always somewhere to duck in when you hear an unusual noise, not so when sleeping under the stars with no tent. There is no where to get away from the unusual, to them sounds.
When it comes to country people in a city it is all the closed in feelings, the lack of openness, and the strange sounds that permeate a city but not the country.
Like you I can pretty much sleep anywhere, and through almost any noise.