"... human nature is much the same everywhere, and, of course, one has opportunities of observing it at closer quarters in a village." --Agatha Christie
You're sidestepping my point about geographic insularity among Americans abroad by pivoting to a general truism about "human nature", which is a polite literary deflection, but doesn’t really engage my observation. What struck me in the 1960s wasn’t sameness of character, but the very uneven geography of who traveled and who didn't. Out of the hundreds of Americans I met on the road, over 95% were Californians, with a smaller sprinkling from Oregon and New York. Only two were from the Midwest, and just one from the Deep South. That imbalance speaks volumes about which regions produced the most inclined to venture beyond America’s borders.