To be fair about most American's never leaving the country, it's a big country. You can spend literal days driving from one side to the other.
If you asked the average American, "What's the furthest you've traveled?" That distance will most likely exceed the average distance traveled by someone from, say, Germany.
The German could have been to half a dozen countries, and never gone outside of Continental Europe.
Say the wrong thing and make things super awkward?