An oldie but a goodie from Michael Copeland: Shipping is a Feature—Some Guiding Principles for People That Build Things:

For these five bits of advice, I chose to focus on what I think is the most challenging aspect of being a PM, which is achieving clarity and maintaining a point of view for a product when all forces work against this very thing. What customers value most in a product is that “it just work” or “does what it is supposed to do,” and yet at every step in a product, the dynamics of design work to make this the most difficult to achieve.

The whole list is good, but the one that resonates the most with me is “Can’t agree to disagree.” What to do when you simply have to make a decision that not everyone agrees on:

So if you’re on the “winning” side of such a dialog then you have to bring people along every day for a while. You can’t remind people who was right, or that it is your decision and so on. If you’re on the “losing” side you need to support the team. You can’t remind people when little things go wrong (which they will) that you were right. Once a choice is made, the next step is all about the greater good. Nothing is harder for technologists than this because as technologists we believe there is a “right” answer and folks that don’t agree are simply “wrong”. Context is everything and remember you have to ship–as a team.