Sometimes you just have to bite your tongue and let people learn for themselves. Today at work I knew what a fellow manager was going to do and I warned him what would happen and that he shouldn't take that actions he did. When I return tuesday I am sure I will find that he didn't listen very well. I planned a lot of the things that needed to be done today and was putting the plan into action when he allowed our subordinates to convince him they couldn't get the job done without changing what I had planned.
I had other work to do, so I went into my office, shut the door and went about that work. As I worked I could hear them replan and discuss how they were going to get the results they needed. First thing they did was to not cover all we had promised, instead went for a minimalist approach..... Next thing you know, they realized instead of streamlining the process to help their cause they hurt it by spreading out the work to even more people...
Do I think they learned anything? Doubtful, Their egos are to big.
I was pissed, but I kept quiet and let them learn, even if only a small lesson.