One of the most important abilities a manager needs is the confidence to say, "I made this decision and the results are my responsibilty." I've seen too many people whose strategic plan is 100% conflict avoidence. This is great for making sure you don't aggravate anyone, but less great for doing work efficiently.

There are times where it's best to complete something that you find out isn't going to be absolutely perfect en route. Simply (?) put, it's sometimes better to finish doing something a slightly flawed way than to half-finish something several times trying to build consensus with every stake-holder. It's okay, situationally, to say, "I made what seemed to be the best decision at the time, this is the reasoning I had behind the decision, and that's why we're doing what we're doing now [even if hindsight says we might gain some small benefit from starting over]."

You can make some of the people happy some of the time, but you can't pick your friend's nose. Nor should you want to.