The Curse of the Cone of Uncertainty

"Truly free?
Then thus I give you my freedom's first greeting!
Since by curse it came to me, accursed be this ring!"
--- Richard Wagner, "Das Rheingold", Scene 4

When I first read about the Cone of Uncertainty, it was a liberating revelation to me. However with time I have observed other side of it.

As the cone predicts, your initial estimates are "wildly inaccurate." They improve with time, but by then your credibility has taken the hit, and your audience may not believe you any more. I think I will call this "the curse of the Cone" (or maybe the "Lying Shepperd of Project Planning", if you prefer a friendlier methaphor :-)

Nevertheless, the Cone of Uncertainty is a very important concept in project estimation. Brad Appleton has a nice collection of links to resources on that subject.