Have compassion on people who become angry easily. The person may have negative feelings about himself. By understanding the source of his anger, you will be able to deal with him more effectively.(Rabbi Pliskin's Gateway to Happiness, p.196)
As regards yourself, if you have chronic feelings of guilt or inadequacy, you are apt to lose your temper easily. For this reason many perfectionists have bad tempers. Since they make almost impossible demands of themselves, they feel tense and strained, which often leads to anger.
While always trying to improve, accept yourself. This will lead to the most healthy growth.