Why write? The answer is two-fold: For the love of it; or because you have something to say or show. We are a sharing species; a storytelling species. If there is a story (or hopefully, stories) inside you, by all means write. More important, learn to write well.
In each of these books, I deconstruct a single story to exemplify the principles behind good storytelling, as well as weaknesses in parts that could have been better written.