That too...I simply love mowing.
I like watching girls mow the grass! :p
I think it's the immediate gratification thing. You run the mower and can see the effect.
Past couple of years I haven't been able to do it as much. There have been some folks in the neighborhood who needed some extra cash, and it's a good way to give them some without it being a handout, so I go along with it regardless of the fact that I'd really rather do it myself. I figure it's not much of a sacrifice, and if it helps them, then that's good.