He who knows, and knows that he knows, is wise; follow him.
He who knows, and does not know that his knows, is asleep; awaken him.
He who does not know, and knows that he does not know, is ignorant; teach him.
[My job; this is what I get paid to do.]
He who does not know, and does not know that he does not know, is a fool; shun him.
[If you keep your ignorance a secret until the exam --- at which point it will be obvious --- you wind up in this category by default, even if you really belong among the ignorant. Would you rather be considered ignorant or a fool?]