@carnage4life
...and then driving alignment amongst leadership! I've seen so many product leaders say "No we can't/won't be doing that" and then a sales leader going out and selling it anyway OR a founder just leaping out of the shower with some Brilliant Idea and expecting it to be prioritized without anything else on the roadmap having to be shifted.
A PM friend of mine used to say, "Product has a lot of responsibility and almost no power."