English Explanation of Pirkei Avot 5:11

There are four kinds of temperments:
Easy to become angry, and easy to be appeased: his gain disappears in his loss;
Hard to become angry, and hard to be appeased: his loss disappears in his gain;
Hard to become angry and easy to be appeased: a pious person;
Easy to become angry and hard to be appeased: a wicked person.
One commentator points out that although the mishnah calls these qualities “temperaments”, human beings have the ability to change their “temperaments” from one to the other. Otherwise the one who is slow to anger and quick to be appeased would not be considered pious, for these qualities would be out of his control. While we might be born genetically disposed to certain characteristics, he can overcome our predisposition. Human beings, unlike animals, have control over their temperaments and therefore their moral attributes can be described by their level of self-control.
Easy to become angry, and easy to be pacified: his gain disappears in his loss: The fact that he is easily appeased is not helpful since he is so easily angered. This person ends up with a net loss.
Hard to become angry, and hard to be appeased: his loss disappears in his gain: The fact that he is “hard to be appeased” is compensated for by the fact that he rarely becomes angry. This person ends up with a net gain, although there is still room for improvement.
Hard to become angry and easy to be appeased: a pious person: Note that the pious person does occasionally get angry. He is not perfect. However, even on the rare occasions when he does get angry, he is subsequently easily appeased.
Easy to become angry and hard to be appeased: a wicked person: This person is constantly getting angry and can never be appeased. No one can get along with him and he is therefore accounted as wicked by most people.