For me there are several variables at play.
After I finished university, I got the opportunity to go and live & work in Japan on the JET Programme. I was single and it was my first time fulltime job. It was in a country that I expected to be very different to my own (but actually wasn't, once you got beyond the surface layer). In this case, I wanted to leave my home-country and experience another.
8 years' after that, I moved country again (having moved back to my home country from Japan). I was dissatified by the way by countrymen  and colleagues handled their newfound wealth. They displayed the financial acumen of children in a sweetshop. In this case, I wanted to leave my home-country and find somewhere where I didn't stick out like a sore thumb. I missed my family and friends and they were only things holding me back.
3 years' after that, I was engaged and the parent company announced that all daughter-companies must be in the same city. My fiancée and I were living in a flat and she was just finishing up her Master's degree. She found a job in the new city within a few months. In this case, the decision to move city seemed sensible. Only my fiancée's family were unhappy. We would only be 100km away. It's not that far.
Now we are married and have a house & children. We are slowly building roots here. The absence of grandparents and kin is noticeable. Do we regret it? A little, but we are happy with what we have so far. I am not especially greedy. I only ever wanted enough of something so that it would never be a problem.
In the past, I looked forward to changing city regardless of whether it was on account of the job or not because I enjoyed the change.
Now, having settled, I would rather not move. I am no longer footloose. Either my current position would have to become much worse or a new opportunity would have to be so much better to justify the commute of moving for a job.
 Hint: it's in Rightpondia...