The Reiki Ideals of Mrs. Hawayo Takata, who brought Reiki to the West from Japan, begin with an injunction against anger.
All of Hatha Yoga is based on a principle of “ahimsa” or non-harming.
Wicca teaches to weigh behavior against “if it harms none, do what you will.”
And so it goes, on and on.
There is something incredibly destructive about the impulses to harm the self or others. Even having the impulse, even saying the word, is on some level violent.
Avoid it for your own sake. The less cortisol released into your blood stream, the healthier your heart and mind will be. And your ability to channel the healing available in the universe will be magnified beyond your imagination.