As some members have pointed out the ultimate demarcation point is the individual but I don't think that answer is valid. Not only does it stop a reasonable philosophical question in its tracks but I don't think it's true; we're a social animal amongst many others as moony pointed out.
It's clearly on a spectrum. My local village, for instance, competed in many ways with our neighbouring villages, as did my local town, county, region etc. But there's no meaningful cultural difference, if we take out the 'artificial' polarizing factors (yes I know), but I think a simplified question may be interesting to explore.
But language is far too near the upper extreme on the spectrum; England, America, Australia, Canada etc...
I sorta know what you mean, the closest I got was reading Les Miserables - Victor Hugo, two books in one, the story and a biography of the culture. Highly recommended and without spoilers.