I am currently reading Writing Brave and Free: Encouraging Words for People Who Want to Start Writing by Ted Kooser & Steve Cox. I've been coming across all sorts of great quotes. Here is one on their purpose for writing the book:
We want to help you write because we believe there can never be too many writers. Why not a world in which everybody is writing? Surely writing, and the contemplative life that goes with it, is a much better way to spend your time than a hundred time-filling activities we could name. Besides, nothing is so exhilarating as to work at something you enjoy, and that's an experience that writing can give you.