As a general rule, I can’t stand project managers. In my profession (web development), they are totally irrelevant—the last bastions for deposed managers. Edward Tufte, famed information depicter, has an interesting thread about their stock in trade, the Gantt chart. It’s basically a way to depict project tasks and dependencies. If that means nothing to you, imagine a to-do list that spans a work team and includes time estimates.
Oops, I may have given away too much there. Let me try again: it leverages the power of information design to illustrate the cross-team interdependencies in a given project and facilitates rapid information conveyance through a paradigmatic convention. Now I’m PMPin’.
Don’t get me wrong, I don’t think they should all be lined up and shot. I’m sure there’s some situation in which they’re the most efficient means to managing a project; I’m just saying that I’ve never encountered that situation.