Metacognitive Miscalibration, or wicked problems and the desire to learn, and other reasons misinformed people think they are well-informed.
Why are the unintelligent or uninformed so arrogantly confident while the intelligent and well informed so often unsure and apprehensive? There is something very human to thinking you know more than you really do about a subject or issue.
Explained in terms of software development.
via Daring Fireball