Peter Principle says- People are promoted to their level of incompetence. A person who is promoted because of his expertise (other than managing people) finds himself at a new level, where many or most duties revolve around managing people, not a technical skill. This means the working world is peppered with bad bosses.
The Peter Principle does much to explain why so many people who are abrasive, thoughtless and otherwise interpersonally inept are in so many positions of power in organisations everywhere.
—I see it all the time in science labs. A top executive leaves and you immediately turn to the best scientist as the replacement.
It’s as if the Chichago Bulls lost a coach and appointed Michael Jordan to replace him. He’s a brilliant basketball player, of course, but the game comes so naturally to him that he may not be very good at coaching other players-he probably never even thinks about how he does what he does.
—To avoid the problem, we set up two tracks, recognising that some people are excellent technical professionals and like their work, but terrible managers and dislike management as a career. Without the people skills they would never succeed at the top levels of management. We tried to spare them the failure of peter principle by keeping them in a professional track.