Rage is disappointment, anger, frustration, etc. that've been stuffed down, bottled-up, squelched. Sometimes the toxicity leaks out. Sometimes it erupts in volcanic proportions.
The pro-active antidote to rage is to learn to express feelings, needs, and concerns in an appropriate, timely fashion. Being nice is unacceptable. We are either nice people or we aren't.
Being nice = stuffing true emotions.
If we believe that God knows our true hearts, how can there be a place to stuff this stuff? As grandma always said, "What's in your heart comes out."