Green grass is one of mans worst obsessions ever.
It needs tons of water / fertilizer / fuel / chemicals / work just to look lame and pathetic.
My yard is a mixture of creeping Charlie, clover, crab grass, and some leafy stuff (the only stuff I get rid of is the spiky ones). I never water it, never fertilize it, never spray chemicals on it, I just mow it weekly. I honk it looks better than normal grass personally.