I think "different" is a big thing, but also what you take away from being somewhere different.
I grew up with too many people who've rarely ever left the state, nevertheless the country, and their worldview is extremely limited. A lot of the people who are not just "USA #1" but more like "USA ONLY!" are the people who've never been anywhere, seen anything different, or really interacted with other cultures. Maybe they've gone to Cancun or even Jamaica, and spent their time at the resort being drunk around other Americans - they went somewhere different and took nothing new away from the experience.
The first time I went out of country (not counting the Mexico border towns) was to England. My friend's family took me to Windsor Castle. The big thing I recognized is that everything in that castle was older than anything to do with our country (a simplification that ignores indigenous artifacts - I get it). How can we be expected to understand the world around us if we never really get to learn about, or experience, anything prior to the 1770s?
You can go to all these different, foreign things, and still not leave with any greater appreciation. Or, you can go to these places, and have these experiences, and allow that increased understanding to become a part of who you are, and how you see things.