http://shareable.net/blog/can-we-design-cities-for-happiness

Older districts are dense (think central Paris and then some), mixed-use , have shorter blocks, often lushly planted medians, and support living needs locally – all in all exceptionally livable. Groceries, book stores, music stores, medical services, some office buildings, clothing shops, etc. are all often just a few blocks away, albeit at different scales. Unfortunately later development, especially after the 1960s has been developed on a highway-like arterial pattern, and is rampant with the highrise-version of suburban gated communities. Essentially all little islands of 99% residential-use buildings scattered on vast wide open spaces, there is no pedestrian integration with the surrounding areas just the immediate surroundings (and no destinations to go to anyhow). There are giant blocks, there is no acknowledgment of the human scale. Not only do people have to travel for work, but to do just about anything else – this development form has generated immense demand/need for motorised travel and reinforces the car-boom that the city is currently experiencing.