The paradox of good writing (assuming you have an iota of talent) is that it takes a lot of time to sit down and figure out all the words and phrasing, but in order for it to be interesting (i.e., for you to have something worth saying), the writer needs to get out into the world and really live life (you cannot be locked up with a typewriter or computer all the time). This is especially true of non-fiction, but also true, I believe, even of fiction (which tends to fall flat when written by a deskbound, adventure-shy introvert).
Hunter S. Thompson is a great example of someone who really lived life (at least, had an excess of adventures) and could actually write, but by his own admission, was something of a crazed maniac. How is this possible by those of us who are not quite so blessed/cursed as HST?