I have a theory that it has to do with isolation. Other than Mexico (which is where Americans go to get drunk for a week at all-inclusives), and Canada, we have no neighbors we can casually visit as in Europe. We're oceans away from other countries. 40% of Americans have never left the U.S. 11% haven't been outside their own state! And more than 50% have never owned a passport. Just a thought about why we're so ignorant.