We are clueless about how long things should take
How it often works:Manager says I want an A that does B?  How long?Most of the time estimate is N days, actual is N +/- 20%.Sometimes it's N days, and you get lucky it's N/3.  Instead of credit, you now have a reputation of padding estimates.Sometimes it's N days, and you go oops, and it's 10*N.  Now you are a slow incompetent.This is why estimation is such a no-win for developers.For areas that come closer like construction, they have centuries of prior experience and often the contractors are big enough to push back.To use the example of this article, go to a boatyard, and say I want to 150 foot yacht with a hot tub and a 20 seat theater, and my budget is $10,000.  You would get laughed out of the office.