Do you pick the city to live in or does the city pick you

I was thinking, do people pick a city to live in or near and then find a job in that city or does the job pick the city for them. In my case, I moved to the DC area to be with my fiancée and found a job there. But I know friends who lived in places then got a job offer in a different city, so they moved based on there job. I know there are different factors for everyone, but over all I wonder why people end up in the cities they do.