I've had a fair amount of experience of different races and nations at close quarters in the last couple of years. Only one difference I noticed between them: some people had good manners and some had bad. But that didn't seem to be connected to their nationality or race.

Sorry to be po-faced, but the guilty snicker of racism conceals something quite nasty.

As for America being enough for Americans to explore - fine if you want it that way! But it's nice to see other places and hear other languages, eat different food, see different customs, and meet new people from quite a different culture once in a while.