"I have every right to be angry!" How many times have you said this or something similar? You rant on in righteous anger about how so and so or such and such wronged you or how "they" should do something about ___________.
You'll defend your position no matter what the cost. You'll tell anyone who will listen your tale of woe, and if you are lucky, you can even get a group of people talking about your issues.
It's easy. All you have to do is start to complain about some injustice, real or imagined, and before too long, other people will join in. They'll emphasize with you and may even add their own story to fuel the fire. If you doubt this, just listen to almost any group of people discussing a current issue.
There is one problem with this entire scenario. The injustices that you are talking about; the bad service you received in a restaurant or whatever is the source of your anger, you are in a vibrational match to the negative situation.
You're vibrating in harmony with something you do not want and from that point of attraction, you can only attract more of it.
But, you argue, I have to talk about it. Maybe, maybe not but, this is important; you do not have to dwell on the situation. While there may not be anything wrong with expressing anger, there is absolutely no value in maintaining this emotional state.
Whenever you are in a heightened emotional state, good or bad, you are attracting the same or similar conditions.
Knowing this, why would you want to keep replaying a negative situation? Acknowledge the situation, maybe even allow yourself to feel angry or upset by it, but then move on. Reach for a thought that feels better than the one you're thinking. Replaying unpleasant events from the past has absolutely no value in the present moment. All it will do is keep you stuck and recreate more of the same.