One of the most interesting promises I made in my life was to stop complaining and make a request when I get upset at someone. I got this from doing a seminar where we were asked to consider making a request instead of complaining. This means you make a commitment to yourself to do something about a situation rather than feeling helpless. You create a world around you that you are empowered and responsible for your situation rather than helpless and upset. And, of course you have to deal with whatever is in the way of speaking to that person with whom you have the upset. Yikes.
The nice thing is that this pushes you into doing something like forgiving, accepting, or communicating, rather than isolating yourself inside a complaint. Any of those things are great alternative options to complaining. It makes a difference.
And, lastly, this is a commitment which I fail to keep all the time. The powerful thing about a commitment is it immediately surfaces all the things in yourself which are in the way of that. At least I get to look at something I have control over (myself) rather than waiting for the world to change.