There is more to leading a self-organizing team than buying pizza and getting out of the way....

 Leaders influence teams in subtle and indirect ways. Great post from Mike Cohn...

http://bit.ly/6iRRqh

Have seen many of our Scrum Masters/ leaders struggle achieving this subtle balance between command and influence Mike is talking about. This is a great skill to have.

Having said that, occasionally one will have to consciously let the team fail, as long as they learn from it and the impact is minimal.

Practice, practice, practice....learning this skill will take you a long way.