If I hear the same complaint time after time again, I say: "I don't want to hear this complaint any more. Either it's not important, then we shouldn't waste time over it. Or it is important, then we should do something about it."
Several weeks I kept hearing at the weekly project meeting that a manager kept poking in the project, changing rules and targets every time, people complaining that this manager was jeopardizing the success of the project.
When I asked "Let's solve this problem. Where can I find this guy?" they said: "You cannot go there! He's the vice-president!" I said "You bet I can go there! If he's jeopardizing the project, he's wasting our time, and putting our and his salary at stake." Eventually they told me where to find the guy, and I went there. I closed the door of his room and said: "Joe, I hear that you are jeopardizing this project. Either you need education, or you want the project to fail. If you want the project to fail, please tell us, because then we can do it much more efficiently. If you don't want the project to fail, we have to talk."
It's lonely at the top. He knew that he was doing something wrong with this project, but didn't know what to do about it, and he thought he had no one to talk with. So we talked about his concerns, and what to do differently to make the project a success. He stopped poking into the project, and things went a lot better.