Private, quiet space is a visceral need for some people and a frivolous luxury for others. In my experience it's very difficult for the people in these two groups to understand each other. A craving for solitude is an expensive trait, but one I have no qualms about indulging: after spending all day in a giant open floorplan and then commuting on a crush-loaded train, if there were Craigslist strangers in my home I'd be in hell.