Can't lie, I came into this thread expecting your friend to be American.
I don't know if I've ever met anyone who never left Germany. I mean you're smack in the middle of a continent where travelling is as easy and convenient as breathing (and almost as cheap). You don't even have to fly if you don't want to, there's literally not a single location in Germany where you can't reach a bunch of countries within a couple of hours with train, car or bus. I can see it being problematic if you live in a huge, remote, dangerous or poor country, but for a German that's a weird attitude to have.