I used to have anger in my teen years and 20s. I learned how to greatly diminish this through Buddhist teachers, from friends, and from personal mindfulness practice.
Evolution of Rage
Let's explore my journey with road rage as an easy example of anger, but you'll see the parallels here with any type of anger.
I believe that anger creates "tumors in your soul". There is a Buddhist saying that being angry at someone else is like drinking poison, and expecting the other person to die.
I believe that anger is self-inflicted violence.
Let's use the driving example again. If you had a hammer in the passenger's seat next to you, when someone cuts you off, would you hit yourself in the head with the hammer?
Of course not! But that is what you are doing if you become angry. You are creating soul tumors which can ruin your day (or longer). These tumors can have both mental and physical health effects if you are often angry.
I was once driving my friend Lucy to Logan Airport in Boston. We were driving in intense, stop-and-go traffic on Memorial Drive in Cambridge. Luckily, we had left my house an hour early, so there was virtually no chance of missing her flight.
Lucy was amazed that the intense traffic did not phase me at all, and that I stayed cheerful.
I had read from Thich Nhat Hanh that when you see the tail lights of the car in front of you, that it should remind you of the smiling eyes of Buddha, and that you have the great priviledge of breathing, right then and there.
Getting angry in traffic does not get you there any faster, so why waste emotion being angry? Just always try to leave early, so that traffic will have no power over you. And smile. :)
Thich Nhat Hanh
For more info about getting rid of anger, a great book is Anger: Wisdom for Cooling the Flames by Thich Nhat Hanh.