I think it applies to management in general, but this is a great article about why library managers tend to suck.
I had a terrific mentor back at Con. U. : Kevin Brandon. It's nearly impossible to put my finger on just what made him so great, but he is the reason I became a librarian. He treated everyone with respect and was infinitely patient with me. He taught me things that I never asked to learn, but ended up needing to know.