"Life becomes easier when you learn to accept the apology you never got."
To stop being angry or frustrated, find the conflict between your expectations or desires and reality, and change either your expectations or reality. Remember, though, you can only change yourself, not others.
Why am I so frustrated?
I went through a period of my life I call my "monk years." I spent these years in intense introspection. One of the first things I pondered was a small frustration I had with a friend.
My friend Sam was always late. Sometimes it was only five minutes; other times it was forty-five minutes. It drove me nuts. No matter how much I reminded, cajoled, or ranted about it, he was always late. My realization about frustration came when I asked myself why his tardiness bothered me. "Because I expect him to be somewhere at a specific time, it screws up my plans when he's not," I said to myself.
And there it was: I expected him to be prompt. Reality was that he was not. That conflict was my frustration. If I remove that conflict, my frustration should disappear with it.
Doctor, change thyself
So obviously I just needed to change my friend and I would be fine. But I had already tried that. My attempts to get him to change only increased my frustration because I expected him to change. It also put extra strain on our friendship.
It took me awhile to realize that the only thing that I can change is me. I can change my expectations of Sam. I can expect him to arrive late. I can make my plans (and how I inform him of my plans) differently to compensate.
I have found in most cases it is my expectations that have to change. That is not to say that all expectations should be changed. For example if you are being harassed at work, you shouldn’t just accept it. You should expect to be treated with respect.
However, if the person doesn't respond to a simple explanation that the behavior makes you uncomfortable, you should expect the person who is harassing you to continue. Yes, you must expect them to continue, because you can't change them, or force them to change.
You must change your reality. In this example the reality that needs changing is contact between you and the harasser. You might achieve this through your employer, however if not, you should find new employment.
Frustration's ugly sister "anger"
As my introspection progressed to more intense issues, I realized that my anger, hatred and many other negative emotions are just more intense variations of frustration. At their core is that conflict between expectation and reality.
I was engaged in my early twenties. Eventually we split up due to irreconcilable differences; she wanted to sleep with other people and I didn't want her to.
It took me awhile to get past the intensity of the emotions to realize that their source was based in the conflict between my expectations of fidelity and the reality that she wasn't. Now that we'd been apart for several years (the reality had changed) I should be good as gold, but I wasn't.
If you look at the phrasing of the conflict above (my expectations of fidelity and the reality that she wasn't), you'll see that the reality in conflict was not our continuation as a couple, but the fact that she was unfaithful. That reality could never change; it is an event.
The answer was to retroactively change my expectations. A better word might be acceptance. No matter how you say it, the fact was that I needed to change to release the anger.
Saying is easy, doing is hard
This understanding of frustration has helped me immensely. While it doesn't make the doing any easier, it is the start of the resolution. The alternative is just being frustrated, or angry, without any understanding or hope for resolution.