Lexicus
Deity
Actually some of that 'make no sense' is specifically planned. The design is so people that don't live there won't be familiar with the layout and not be able to use the area as a shortcut. This drives down traffic congestion through out the community and improves the quality of life there.
No, it improves the quality of life in the neighborhood by increasing congestion everywhere else. Neighborhoods planned to minimize thru traffic also result in far more energy use than if you just lay streets out in a sensible grid.