Reasons to use a human-powered lawnmower

Why I love human-powered lawnmowers -

• Free exercise
• No unpleasant internal-combustion exhaust fumes
  
• You can mow in early a.m. without irking your neighbors
• and finally...the rote work of it is, somehow, ideal for facilitating rumination (of the cognitive variety, if you lack livestock; or of both types, if you've got them.)
  
  Update: Yow - I had no idea. It turns out that rumination, of the psychological variety, means chewing over upsetting experiences; I'd thought it just meant sifting for pattern & understanding.
  (Which it also does: "to meditate or muse; ponder." (link))