Many people who are actually in charge of leading a group (supervisors, etc) are not very good at it. I think this must be true given how many people I know who are not inspired by the work they do for their supervisor.
I recognize that this is easy to say from the sidelines. I am not good at supervising the work of others (nor have I had much occasion to practice), but I still am a keen observer of the employer/employee relationship, and I have held many jobs from which I can observe different methods.
I think one of the most important features of an effective leader is confidence, if it is rooted in competence.
How do we build confidence?
Triathlon helps, even if clearly outside the workplace.
I think education and awareness helps. People can change and learn, and if done well, even the same leader can sometimes turn things around in their own organization.
Here are some other interesting resources I have come across lately:
The Office without a**holes – Adam Grant podcast titled WorkLife (if you work for someone you struggle with, or recognize that those you lead do not seem to work well for you, then listen to this!!!)