Most people write for pleasure.
The pursuit can hardly be bettered. Poetry is the most versatile and wide-ranging of literary forms, enabling things to be said that cannot be encompassed in prose. It can be finished in odd moments, unlike the novel, which takes long years of effort. Whatever its standard or style, a poem can usually be published somewhere, given the determination, the research and the contacts. Poetry forms a good introduction to more commercial types of writing, and is usually included in creative writing courses.