In his book: Leading Self-Directed Work Teams, Kimball Fisher’s comparison between sheep herding and shepherding presents an interesting metaphor for a traditional Project Manager versus a Scrum Master.
The purpose of the sheep dog is to move sheep from A to B. Focusing on the flock itself, it achieves this by directing the flock from behind using barking and heel-nipping. Through this behavior the sheep become dependent on the sheep dog. A sheep herder drives a subordinate flock. Sound familiar?
In contrast, a shepherd develops a relationship of trust with the sheep. From out in front of the flock, the shepherd focuses on the surroundings and clears a path for the sheep to get safely from A to B. A shepherd leads as an example and is constantly on the look-out for dangers in the environment.