"If you can't explain it simply, you don't understand it well." - Albert Einstein
Besides being a genius, Einstein was a very public face for science. He used his fame and popularity to his push political issues and other scientists came to him when something needed to be communicated to the public. This quote seems both appropriate coming from him considering his role as a communicator in an field where many are not, but also surprising since it we tend to put Einstein on a pedestal to the degree that it seems odd that he would have any experience at all with not understanding things.