I can think of several things. First two are about heat. Cities are heat islands, maybe they 'like' that, because they have to burn less calarories while being

I can think of several things. First two are about heat. Cities are heat islands, maybe they 'like' that, because they have to burn less calarories while being there in general. Second, maybe they utilize thermal updrafts rising above such heat islands, a.k.a stack-effect? And then the lights. Maybe they like them?