Hi, Page - great post:)

First:  You win the contest for Catchiest Title ... very clever and engaging:)

Second:  You make strong and eloquent statements in support not of being "mean", but of being professional, focused, and a real manager.  Too often, we shrink from doing what is necessary to help another improve their performance because we fear their response (to a lesser or greater degree).

After all, who wants to be known as a "Mean" person?

I believe that in almost any situation involving coaching someone to a higher level of workplace performance, productivity, or behavior is going to include all three types of "Mean" that you describe.  Take the "mean" word out and what you have left is solid effective and professional management -  balanced, focused, and insistent on standards.

Really like this post ... keep 'em coming:)

John