When the Ontario Science Centre opened they had two plexiglass displays housing mice with different population densities. In the display with higher density the mice were smaller, less healthy and more likely to kill each other. The display's written part questioned what effects would increasing population density of urbanization have on humans?

Would humans be more adaptable and develop skills to thrive in high density? There are extreme examples of our failure to develop those skills such as gang violence. There are also less extreme, more common examples such as dog and car ownership. 

High density urban living has benefits and people increasingly are moving to dense urban centres to enjoy those benefits. Those benefits require adaptability and increased social skills. Accommodating each other will involve developing better ability at not imposing on each other.