Anger is the third stage reached after the initial stage of shock from an event and the second stage of sadness in the process of grieving. We often have others in our presence during this third stage who try to stop us from being so angry when anger intensifies with forms of blame attached to someone rightly or wrongly. However this can derail or delay the grieving process.
Anger is necessary in order to search for what could have been, even with forms of blame attached. Temporary blame can personalize the wound at deep levels needed for true healing and forgiveness to begin to occur, though self guilt may be felt from the blame.
Anger's search for what could have been reaches its purpose when the search ends in acceptance of what is. Then I can say I am what I am and life begins anew for me.