Re: US/UK dual citizenship - passport misery
OFBSLF
Paris to Berlin is 650 miles.
Please note that no passport is required between Paris and Berlin either, but I would assert that the cultural distance is thousands of times that of Boston to the West Coast.
And that's the point. Europeans are much more international in perspective, as we have far more cultures packed into our locale, one can go from the Slavic end of the Balkans to North Africa in a couple of hours, for instance.