The simple lesson the essential lesson in one phrase is that anger is not good or bad. When it comes to middot , you need to be like a kid in a candy store. What you need to say is, I ll take two of these, five strips of those, an ounce of that, and a full scoop from that barrel. That is the way the Jewish tradition wants you to build character. If it is one of the voices in the choir that is your soul, then it is there for a reason.
Nothing needs to be purged.
Nothing needs to be beaten out. God blended in everything that is you on purpose and for good reason. Your inner-self cannot be divided into good feelings and bad feelings, rather your job is to put them in balance. The shock we feel at evil being very good is intentional. This midrash goes on to explain that it is only because of the Yetzer ha-Ra , that couples make babies, establish homes, open business, are competitive, and even become public leaders.