Do flies do any good?

Flies seem to be an icky nuisance, buzzing around trashy, dirty places, but that's because they help to clean up those dirty messes! When flies are juveniles, maggots, they seem gross to us, but they very quickly consume and clear up dead animals and plant materials. They are nature's garbage men keeping ecosystems clean! And not only that, they are food as flies and maggots to lots of other bugs and vertebrates like spiders and lizards!