Ignorance + Arrogance = Idiots
There is the blissfully ignorant and the knowledgeable / know-it-all arrogant. But the combination of both is something truly special. People too arrogant to want to know more and arrogant enough to impose that no one else should too. A person too ignorant of what others know and ignorant enough to assume they know more than everyone else. I present to you the Idiot.