Years ago I coined a term for a number of people I deal with in business -- "arrogant ignorance." I don't mind running into folks who are young and inexperienced and admit such -- in fact, I like educating and training people and sharing what limited knowledge I have accumulated. But what really sets me off are folks who have no idea about the subject on which they are making decisions but act as if their judgment is beyond question. This tendency seems to be reinforced by organizations that have few real performance metrics and where, as such, looking like one knows what he or she is doing is more important than actually doing anything.
More recently, I found that this effect already has a name - Dunning-Kruger, though I think my term is much more evocative. Anyway, this is an interesting article on Dunning-Kruger and its legitimacy in describing actual human behavior.