Riding a bike around town, you see a lot of happy things that you didn't used to see. You also see a lot of sad things that are hidden just slightly out of view of the passing cars.
It turns out that there are a lot of homeless camps in Los Angeles, though they do their best to keep hidden (they don't really build tree houses and wave at the passing cyclists). On a bike, you are down there at street level. You see, hear, and smell absolutely everything. It's magically uplifting and hauntingly depressing at the same time.
I guess that's just a good description of all mankind, really.