Of course anger is a legitimate feeling. It can't be helped, and I would even dare to say that it's sometimes healthy. As much as I claim to be a fun and happy person, I will confess freely that I do get angry from time to time, however, as I do not believe in the phrase "Revenge is a dish best served cold" , I decided a long time ago that "giving up" without forgetting was the best option for me.
My blood pressure would go up. I would get more headaches. I would be unhappy most of the time, and people could tell. I was NOT a person you would like to hang out with for a while. More withdrawn, sadder, I did not know how to appreciate life around me.
I have no idea when this all changed. It took me a while to become so "zen" about things (I am not a zen person at all, heh) that I can now get angry, think about it (those "heat of the moment" arguments are the worst, I think) , and get over it within a day or two. And then, I simply remember and may, from time to time, mention the events again, but in that detached "look what I saw here here and here" way, when you tell friends about some new things you have discovered.
Being angry all the time is counter-productive. Just like being stressed about everything all the time will never help. I am still not as calm and relaxed about things as I wish I was, but the good news is, for me at least, that I am getting there.