Why not to be a Yuan Shao
Yuan Shao was, for a time, the most powerful warlord during the Three Kingdoms period in China. ... and he lost it all. Why? Because he was an idiot. He followed faulty advice, couldn't act decisively(and when he did act decisively his actions ended in catastrophe because he would somehow manage to choose the worst plan possible), he let his pride affect his judgment and would promote the famous and the well spoken over the talented and worthy. So he was destroyed, by a much smaller foe that did the opposite of what Yuan Shao did - Cao Cao listened to good advice, had good strategies and went through with them and recognised talent when it wasn't attached to a well-known name. So Cao Cao won some key battles, Yuan Shao died, his lands split among his sons and soon after, everything fell apart. So the lesson of this story? Don't be a Yuan Shao. That's all.