The necessity for leaders to possess optimism and ego serves to answer the age-old question: Are leaders born or are they made? They are born. A leader is born with an optimistic disposition or she is not. If she is not, then no amount of "optimism training" is going to make her view the world in an overwhelmingly positive, opportunistic light.
In the minds of great managers, consistent poor performance is not primarily a matter of weakness, stupidity, disobedience, or disrespect. It is a matter of miscasting.
People leave managers, not companies