Whether you show or repress anger in dreams is important. This is because like any other basic or instinctive response, anger uses tremendous resources of emotional and physical energy. The repression of emotional energy can be a key factor in the breakdown of health, and lack of positive and creative self expression. Blocked emotional energy tends to attack your sense of well being and body if it is stopped from expression.
In some dreams enormous anger is expressed, but it is accompanied by a sense of frustration because the anger brings no satisfaction. Dreams are a safe place to express anger.
Anger may be a way of hiding vulnerability or real pain. In this case, it is important to feel the anger and discover what is underneath it. Sometimes deep feelings from childhood emerge once the anger has been felt.
Do I satisfy my anger in the dream? (If not it is worth expressing it in some way while awake. Use a rolled up newspaper to hit an armchair or cushion with. See if you can get the feelings in the dream flowing.)
Can I feel what this anger connects with in waking life?
Is there a way I can assert myself without being destructive?