You probably suffer from the "illusion of explanatory depth." Moreover, you often succumb to the "illusion of understanding." So say two cognitive scientists, Philip Fernbach of Colorado University and Steven Sloman of Brown, in The Knowledge Illusion: Why We Never Think Alone.
Disagree? OK, then write down how a zipper works. Or draw all the parts of a simple bicycle in their proper places. If that's too complicated, tell me: How does a flush toilet operate?
If we are all so deeply ignorant, how is the modern world possible? The book's answer is that we live in hive mind where knowledge is distributed throughout the human community. We are, in the authors' words, "built to collaborate."