I have one thought to make you feel better on those rough days of planning, prioritizing and accepting work from your team.
There are just days you get frustrated and need a good laugh. When that happens, please check out regretbeingaproductmanager.tumblr.com. It’s mostly animated gifs with tag lines related to what we do.
It won’t improve your team’s velocity or the scope creep from business, but it keeps the jaded scowls away for a few hours. Enjoy, and be sure to follow them on Tumblr.