I personally don't feel the desire to visit other countries. If it's not somewhere I'd want to live, it's not somewhere I really care enough about to see. I care more about experiences and knowledge, both of which can be had where I live.
It helps that my state is also comparable in size to larger European countries. And has a pretty dynamic environment. Very mountainous and foresty in the north, planey in the east, red desert to the south, and tan desert to the west. Blazing hot in the summer, and well below freezing in the winter. I still haven't seen the majority of just this state.