>I've been the manager on the other side of a lot of situations that could be described like this. In many cases, it was hard to explain to the person that there were dozens and dozens of inputs that go into my decision making, including a lot of invisible factors and relationships that I was juggling.

I think this is also a really important counterpoint -- sometimes the person who "cares too much" is simply wrong, and is causing problems that should be avoidable. In other words, without more details it's hard to know if it's the manager or the direct report who is really the problem here.