This grief and anger often leads to the bottle or some other libation. In contrast to the Indian anger is the non-Indian fear or guilt. It is a collective thing faintly felt. Some will argue it does not exist, but most Americans that know the true history of this land feel remorse. Others feel justified.
Anger is an emotion that usually develops between characters arising from some failing or another.
Sometimes it is much deeper. Indian anger is a deep sense of betrayal not unlike the African American anger or the Jewish anger. It is the same feeling a person would experience watching their own mother being kidnapped, raped, tortured and, finally, murdered. This kind of anger is so extreme that characters fully involved in it are apt to destroy everything around them in a blind fury. Combined with the sense of enslavement that accompanies the loss of freedom and the knowledge of the genocide since contact and you might wonder why more Indians aren't mass murderers.