I often fantasize about leaving "my" city of Frankfurt/Germany, but I always wonder if anywhere else is actually better for ME, wherever on the bell curve I might be.
Before I was 30 I became CTO of a great company here, i really wonder if I had made such a career anywhere else if I'd moved to somewhere with a more vibrant tech-scene where my specific skill combination isn't as relatively uncommon as it is here.
Same with my lifestyle situation of being the working Dad in a one-income household. Doesn't matter that i'd be making a killing in SFBA if living with a family simply costs so much more there.