In the past, if you traveled from San Francisco to new Orleans you would experience an entirely different set of stores, a new dialect, new customs, and frankly a new language.

Even the difference between California and Oregon is stark. California being mainly Hispanic and Oregon being mainly Nordic and with lots of Slavic influence. The names change and even the languages do.

I'd never see Russian in California but it's a regular occurrence in Oregon.

EDIT: By no means am I suggesting though that Americans do not have fondness for one another. I just think the relationship between a rural Alabaman and an urban Californian is more like the relationship between two citizens of differing EU countries. We certainly have a shared culture of sorts, and we will defend each other in the face of non-Americans, but there are cultural differences that cannot be simply glossed over.