A person can perform only from strength. One cannot build performance on weakness, let alone on something one cannot do at all.
Peter DruckerMost Americans do not know what their strengths are. When you ask them, they look at you with a blank stare, or they respond in terms of subject knowledge, which is the wrong answer.
Peter DruckerThe great mystery isn't that people do things badly but that they occasionally do a few things well. The only thing that is universal is incompetence. Strength is always specific! Nobody ever commented, for example, that the great violinist Jascha Heifetz probably couldn't play the trumpet very well.
Peter Drucker