It's not getting started or knowing when to stop. It's figuring out when to put it out to the public. As long as you keep it in your head or computer, you can keep tweaking it, rewriting it, playing around with it some more. You can optimize and optimize all you want. Sometimes you might realize how crappy it is and start over. But once you put it out, it's out and you have no real way of taking it back. Sure, it can be deleted, but is it really deleted from everyone's minds?