There is maybe one point missing. Planning. I know a very little programmers (and I am happy to be among them) who can almost exactly tell you how long they will work on something, even if it's something they never work on before.

But I know a lot of programmers, who are not able to tell you anything, even if they are working on almost the "same thing" they are working on for last X years. And if they tell you, you can bet, that it will be delayed.

The reason for this - from my perspective - is planning. They majority is not able to think ahead about the code they will work on.