Comment by ChuckMcM

And, perhaps not surprisingly, I think that last example "Not good at selling themselves" is also bad management. While everyone loves flattery, managers who aren't comfortable being objective with comparing work productivity are bad managers. I cannot count the number of times I wished there was something like codeacademy.com for learning management skills.

One thing that impressed me about IBM, during my brief tenure there after the Blekko acquisition, was that they had a very deep catalog of online self paced training material for developing manager skills. I don't know how many people availed themselves of that resource but since that time I have really wished I could have pointed people who were struggling at some of the courses they had.