I'm throwing this out as a follow-up to favorite cities and countries. I partially answered (ignobly) in the question from ChrisF where I answered why I had not listed UK places. For me, like I said, despite tons of German language (equivalent of 5 years with As to A+s), I still cannot speak it well. With only 1-1/2 years of college French (but living there) and a Fluenz.com Italian program 1-3, I feel totally at home in France and Italy. Things have changed a whole lot since I was first in France in the 1980s, when there really was Gaullist feeling. Now everyone wants to talk to Americans, at least in Paris.
For me, the other thing is discovering past historical loves. While I started at Wellesley (still married), I did languages and medieval history, but when I transferred to Harvard I had to work courses around my work schedule and took anthropology, archaeology, classical civilization, and whole lots of stuff to do with Greece and Egypt. And I loved it! So I've come back to that now, along with my love of France and Italy (and Andalusia).
Besides work, why do the rest of you go where you go?