Anger in a dream commonly surfaces when a boundary has been crossed and the frustration around it hasn't had anywhere to go in waking life. Lashing out at someone in the dream can point to injustice you've been absorbing quietly, a reaction you've suppressed that's finally demanding to be felt, if not yet spoken.
The lord of the second house hath the same strength in hurting, as the lord of the eighth; the lord of the sixth, the same with the lord of the twelfth. - William Lilly (1602.-1681.)