What makes these three words (the title of this post) so hard to say? Does it suggest ignorance, incompetence or lack of intelligence? In the investing world, the phrase is probably not used enough, which may lead to the very dangerous state whereby one thinks one knows something, but really doesn't.
The author of Freakonomics (whose book is summarized here) takes a closer look at this phrase, and how its incentives are aligned in the business world.
You can listen to the podcast here, and check out the follow-ups here and here.