Anger

I think the reason why anger is power is, when people are angry, they are out of mind. They are driven by their emotion but not their mind, which means they can't calm down and think about what should do, what should not do. Therefore, things can be out of control when people are angry. 

I heard a story about a tragedy happened because of anger. In a small bar during New Year's Eve, two people have an argument because one people accidentally step on another's foot. The one who got step on get so mad that he throw the bottle to another people. Then they fight with each other. However, they throw a lot of things to each other, so more and more people get hit and at last all the people at bar get into fight. Lastly, police come and all of them get arrest during New Year's Eve.

If people can calm down for 10 minutes and think about the case every time before they trying to argue with other people, and other people can help to stop the fight at first time, this tragedy can be avoided.