The Bitterness Addiction
Most people have experienced injustice and cruelty which, if left unchecked, could leave them sipping from the cup of bitterness for the rest of their days. It may be impossible to erase such memories but it is important to contain them. If they continue to play a role in your life, you will be as subservient to them as an addict is to heroin. You want to take whatever positives can be gleaned from the experience and move on.
Don't expect others to empathize or understand. They have problems of their own and besides, you can waste large chunks of time wondering why this or that person didn't behave nobly.
Consider people you've met who have become addicted to bitterness. Odds are, you would not want to be any of them.