During the past year, I did some consulting for a project that was proceeding so smoothly that the project manager knew she would deliver the product on schedule. She was summoned in front of the management committee and asked for a progress report. She said she could guarantee that her product would be ready by the deadline of March 1, exactly on time according to the original estimate. The upper managers chewed over that piece of unexpected good news and then called her in again the next day. Since she was on time for March 1, they explained, the deadline had been moved up to January 15.