Anger, though being a negative emotion, can be used as a tool if you know how to control and maneuver it. Kinda like how professional boxers and wrestlers use it as a motivator without letting it take over them.
But then again, most of us aren't boxers, so let's just keep our punches in our pockets.
That's the point. 99.99% of the people don't know how to manoeuvre it and so most of the times, it ends up doing bad.