If the words or actions of another produce the emotion of anger, the initial step should be internal exploration. Your neural vaults house many deposits that only exist to serve your ego and ideals.
That being said, anger is not a wasted or negative emotion, it just requires more processing. If the reaction of anger is deemed valid, it can then be channeled into positive action or response.
Refusal, Resistance, Rebellion, and Revolution are all products of anger. In spite of traditional definitions and negative connotation, ALL can be carried out peacefully and with positive intent.