I quite like regionalism that doesn't align with national borders. An example would be "limburgers" have a strong shared identity, even as parts of it lie in Belgium, and parts of it lie in the Netherlands.
Fundamentally it comes down to this question, I think: people tend to like to be around people that've shared a same background, is that ok? And to what degree?
Oh how I long for the day someone invents a car without a touchscreen.