It is often said that the more you know, the more you realize how how little you really know. On the flipside, however, its contrapositive indicates that the less we know, and the more ignorant we are, the more delusional we are about the level of our knowledge. Hence:
Vanfair Maxim #57. Even the highest degree of intellectual humility is insufficient to subvert the natural human tendency to underestimate our own ignorance.