Only from strength Most people think they know what they are good at. They are usually wrong. More often, people know what they are not good at—and even then more people are wrong than right. And yet, a person can perform only from strength. One cannot build performance on weaknesses, let alone on something one cannot do at all. Peter F. Drucker, Managing Oneself strengthweakness
Using your own expertise Almost all professionals are slow to use their own expertise for their own work. The situation is nicely summarized by the old saying, “The shoemaker’s children go without shoes.” Richard Hamming, The Art of Doing Science and Engineering: Learning to Learn The cobbler's children go barefoot