I moved from a city with a population of 700,000 to one with 12 million, then to one of 200,000 and now am preparing to move back to the 700,000 one (yeah, confusing for me too). I spent 12 years in the big city and had some amazing experiences, but the commute, air pollution and crowds did me in as I got older. I'm not ruling out the possibility of moving there again at some point, but it would be as a temporary thing. My mental health got much better once I moved out.
Leonard Cohen (Bird on a Wire): I have tried in my own way to be free
Mrs Hudson (BBC Sherlock): Sherlock! The mess you've made!