Because I'm Welsh some would say I possibly have a questionable tendency toward sheep. Slander, I say. Nevertheless, I found Kimball Fisher's comparison between sheep herding and shepherding to be an amusing and interesting metaphor for a traditional Project Manager versus a ScrumMaster.
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 behaviour 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.