A revealing passage from Ed Catmull of Pixar, via intenseminimalism.com.:
In the process of making the film, we reviewed the material every day. Now this is counter-intuitive for a lot of people. Most people—imagine this: you can’t draw very well, but even if you can draw very well, suppose you come in and you’ve got to put together animation or drawings and show it to a world-class, famous animator. Well, you don’t want to show something that is weak, or poor, so you want to hold off until you get it right. And the trick is to actually stop that behavior. We show it every day, when it’s incomplete. If everybody does it, every day, then you get over the embarrassment. And when you get over the embarrassment, you’re more creative.
As I say, that’s not obvious to people, but starting down that path helped everything we did. Show it in its incomplete form. There’s another advantage and that is, when you’re done, you’re done. That might seem silly, except a lot of people work on something and they want to hold it and want to show it, say two weeks later, to get done. Only it’s never right. So they’re not done. So you need to go through this iterative process, and the trick was to do it more frequently to change the dynamics.