"If, therefore, you desire to attain perfection and rightly pursue the spiritual way, you should make yourself a stranger to all sinful anger and wrath. Listen to what St. Paul enjoins: Rid yourselves of all bitterness, wrath, anger, clamor, evil speaking, and all malice (Eph. 4:31). By saying ‘all' he leaves no excuse for regarding any anger as necessary or reasonable. If you want to correct your brother when he is doing wrong or punish him, you must try to keep yourself calm; otherwise you yourself may catch the sickness you are seeking to cure and you may find that the words of the Gospel now apply to you: Physician, heal yourself (Luke 4:23), or Why do you look at the speck of dust in your brother's eye, and not notice the beam in your own eye? (Matt. 7:3).
In contrast to this, we may feel anger at our kids when they transgress, but we are able to put the anger aside and correct them calmly and discipline them as necessary and helpful, without losing ourselves in the emotion of anger.
Anger can be a sign that something is wrong, but we must quickly observe it, use reason to pass judgement on ourselves and clarify the situation, then act calmly and lovingly to correct the situation if need be.
I think we must detach from emotional situations--see ourselves as not "of" them in order to react righteously to events. We feel passionate, emotional, rageful when we take things personally--to put it colloquially. The anger we might feel at an unjust situation--racist remarks, for instance--should quickly resolve into a loving correction and a realization that we are as sinful as the one toward whom we feel anger.
Of course, all this is easier said than done. I find myself feeling more anger at total strangers than at anyone I know--Democrats, for instance, and other drivers. I have to pray constantly for detachment--for not seeing anything that occurs in my life as ultimately important and for recognizing that God is in charge of all things. Then I can either let things go or work in a rational way to correct them.