The whole world is California, and the most important thing we can do is pack more and more people into the same space. People from here, people from there. We want more crowdedness, and everyhing that comes with it: crime, noise, pollution, lack of social cohesion. Everything. Every place must be like this, and everything must grow forever.
Negatives acknowledged, there are huge efficiency upsides to dense human living. Everything becomes smoother, faster, less wasteful. You get a society that leverages economies of scale for everything.