Anger in a dream at someone you know is usually an expression of pent-up hostility toward that person. In waking you may not be able to express your anger, because you do not wish to hurt their feelings or they may be your employer. In sleep anger comes out because you have to vent it in some fashion. If you dream that someone is angry at you, then this means that you either suspect that the person in real life is angry at you, or you have that particular paranoia.