For gardeners, the worm's purpose is to chew up grass cuttings and vegetable peelings and torn-up cardboard and produce compost.
For worms, the main purpose of the gardener is to provide a regular supply of grass cuttings and vegetable peelings and torn-up cardboard.
So there is a pleasing symmetry between the purpose of the gardener and the purpose of the worm. For religious folk, both the worm and the gardener are fulfilling God's purpose. [Trinity Ranch: Worms and Weather]
Shep (aged 15) thinks a similar equation also works for slugs: The Slimy, yet Special Slug. Many gardeners find it difficult to respect the purpose of the slug. Religious people might say that God created hard-to-love creatures on purpose, but of course that explanation is at a different logical level.