21 Rules of Thumb for Shipping Great Software on Time:
"You should reward and treasure those who consistently make themselves aware of the list of relevant things that are currently unknown. It requires mental and psychological strength to resist the normal human cravings for certainty and order. It especially difficult to believe in uncertainty when things have a veneer of orderliness, which is often the case. Pseudo-order is a maladapted defense against uncertainty."
"The organization surrounding you will undoubtedly abhor uncertainty, would infinitely prefer pseudo-order and will make countless attempts to magically convert your ignorance to knowledge. Your job is to make uncertainty an unshakable fact, and to coerce the reshaping of the surrounding organization to cope with the uncertain situation. The organization must learn to thrive in an uncertain environment for its own well being."
"...with each slip, you and your team are spending your credibility. It is essential that after a slip, the next milestone be hit. This is so the team believes in their ability to manage the project, and so that the reserves of credibility are rebuilt for later consumption."