"...what use is anger when the same end may be accomplished by reason? Anger is not expedient even in battle or in war; for it is prone to rashness, and while it seeks to bring about danger, does not guard against it."
REBT helps you transform unhealthy anger into a productive or healthy negative emotion. Our language does not have a good choice of words for this healthy "anger". We might use words like healthy anger, healthy frustration, annoyance, displeasure (as in displeased with someone), or disappointed (again with another). Do not suppress or hold onto your unhealthy anger but relinquish it! How you ask? By disputing your "arrogant" and "mythical" demands for those things you value. I recommend keeping your value but relinquish your demand which you unwittingly place on your value. See that the below belief is flexible and true (i.e. is not a myth):
"I wish to be treated fairly but you do not absolutely have to do so. If you had to treat me fairly you would be compelled by some currently nonexistent force to treat me fairly. Unfortunately this force does not exist as it is plain to see that nothing compels your behavior."
Once you adopt this belief you can with a clear head decide on the best strategic response, move, or assertion to make now at or at some time in the future. Without anger you can decide to attempt to influence the other or you may decide to exit the relationship and have a go of it with another person, firm, or partner. Unangered but displeased or annoyed you do what is best in the long run all things considered.
I often think of the road to anger as something like a race. I try to remind myself "The first person to anger loses". Here I see myself in a race to an emotional destination I wish to lose because I thereby gain leverage in the situation. Stay flexible to stay unangered when others misbehave. This may be difficult to sometimes do but you are capable of it even if it requires work and practice.