I like poetry because poetry - even in free verse - is formal, and it has to be very concise and packed and rich, and I like the feeling of having to do that, having to make the language tight and still free, as if the deepest freedom is created by the restrictions.
Poetry uses language to create a music borne inside human experiences and emotions.
Poetry doesn't function by saying things straightforwardly because the language is too imprecise, too limited often, to address the underlying subject of most poems.
I approach writing a poem in a much different state than when I am writing prose. It's almost as if I were working in a different language when I'm writing poetry. The words - what they are and what they can become - the possibilities of the words are vastly expanded for me when I'm writing a poem.
Poetry is very playful with language. I think all poetry, at its heart, is playful. It's doing unusual and playful things with the language, stirring it up. And prose is not doing that. Primarily it's not attempting to do that.