In the period of rapid growth following the announcement of System/360, IBM found that it had converted high performing engineers and programmers into poor managers. The problem was both lack of training and differing personality types. I'm a Myers-Briggs INFP while my direct opposite, an ESTJ was"was born to manage" [
http://www.knowyourtype.com/estj.html]. IBM had dual promotion ladders below the executive level so that I was promoted to senior engineer without being made a manager.