Great advice if your goal is to be destructive to yourself and others. I am recovering from abuse and can for sure say that nothing good has ever come from, or will ever come from anger. We're all angry from time to time. And it's still destructive as its only quality. Being violent in thought or action is not useful. Ever. Only apologists hiding from reality will say that being angry was good. Every scenario you can pose is better met with good temper. Even under actual physical attack, a calm collected response leads to superior outcomes. There is no real world use for anger. It is a remnant hunter gatherer feature.