I tend to hang out with the other expats in the office, mostly because each of us has a maximum of two friends outside of Monitor living in South Africa. I was recently at a dinner when I realized that we were all from different continents - North America, South America, Europe, Oceania, Asia - very small world, in a Disney sense of the phrase.
So, as with study abroad in college, there is always the convenient conversation topic available here of "What's _____ like in your country? Oh wow! That's a little weird but I guess it could be normal if you're used to that..." This can apply to pretty much anything. It's a little more interesting than in college though, because the questions don't apply only to comparing college lives. Having those conversations at 25 yrs old as opposed to 21 yrs old gives you a much better sense of the meanings of family, independence, money, security, free time, etc.
I think the place I'd have the hardest time living would be Korea - work 100+ hour weeks as a consultant and live at home with your parents until you get married. Brazil has the whole living with the parents thing, but you work 30-40 hours less and go surfing instead - and you get a government-mandated lunch allowance from your employer. Spain has the whole siesta thing going on though. Hard to beat that. Of course, in terms of the questions I get about the US, the old favorites do come up every now and then, namely - "How can you not drink until you're 21?!" "How could you people have elected that guy twice?!" "What exactly is a fraternity?"