I disagree that it cripples the other points. I just think that a lot of people try to find all of the failure points before they start. You can't start without having a bit of direction (I reference a book to use in my first post) but don't think about where the road will end up, just get on the road.
I would say this last point is the most important one. And it also kind of cripples most of the other points.