Mishnah 11 - Chapter 5 - Pirkei Avot

There are four middoth in deoth (temperaments): easily angered and easily pacified — his gain is negated by his loss; angered with difficulty and pacified with difficulty — his loss is negated by his gain. [If one is quickly angered by all things, even though he is easily appeased, his loss is more than his gain. For most of his acts are defective in that he is easily angered over everything. But if one is angered with difficulty, even though he has the evil middah of being pacified with difficulty, his (relatively) small loss, being pacified with difficulty, is negated by his (relatively) greater gain, being angered with difficulty, so that most of his acts are praiseworthy. Some versions are the opposite of this; but this seems to be the correct version.]; angered with difficulty and easily pacified — a chasid; easily angered and pacified with difficulty — a wicked one.