is there a healthy anger?

When I defend myself against an assult designed to destroy me, that is healthy. When I attack people because they remind me of a rejected part of myself - try to stamp out that image and throw away their feelings along with it - that is unhealthy. One response affirms and builds, the other judges and tears down.

Why can I easily get angry at him and not even feel it toward my boss, who sometimes abuses me? I must be afraid of losing something and so turn on myself to undercut the aggression. He berates me and I immediately start seeing "truth" in his criticism and so become the only weapon that can harm me.