Servant leadership is an idea that was first developed by Robert K. Greenleaf in 1970. There has been a lot written about Greenleaf's increasingly popular ideas over the years. Without doubt managers could better motivate employees by behaving like servants.
Leaders determine direction, managers execute it.
Determining new directions often requires boat-rocking single mindedness that may run contrary to the needs of followers. The management task of executing direction does require the nurturing of subordinates, but this is not leadership. It is not so obviously a contradiction in terms in public sector organizations where direction is more or less fixed and effectiveness is only a matter of providing excellent service at high quality and low cost. In fast moving markets where constant innovation and new directions are regularly sought, leaders cannot help but make people feel uncomfortable at times. Their focus must be primarily external , not so much internal on the needs of followers.