An hour of reflection by Jez Humble
Value is what gives your life meaning... The trouble with estimates is that they're wrong. Especially as predictions they're terrible as they set up the wrong expectations.
Estimation is not just valueless, it actually has negative value because people have the wrong expectations. People expect your estimates to be right! And the one thing I can tell you about your estimates is that they will be wrong! And that sets up bad expectations.
What estimation does do, is estimation helps create a shared vision of what you're going to build!