An interesting parable due to Niels Bohr:
Once upon a time a young rabbinical student went to hear three lectures by a famous rabbi. Afterwards he told his friends: “The first talk was brilliant, clear, and simple. I understood every word. The second was even better, deep and subtle. I didn’t understand very much, but the rabbi understood all of it. The third was by far the finest, a great and unforgettable experience. I understood nothing and the rabbi didn’t understand much either.”
Came across while reading “Proving Darwin” by Gregory Chaitin.