Maybe you're angry at someone else for the way they treated you but you don't feel that you can confront them about it. Maybe it's a supervisor with the backing of all their higher-ups. Or your safety may be an issue.
Or maybe you're angry at yourself for having tolerated bad behavior from others. Especially if you've been doing this for years because you've never felt comfortable confronting your abusers. You may not even know how to tell them that their words or actions hurt or offended you.
What can you do? First of all, your feelings are legitimate. Don't automatically dismiss your anger by telling yourself that you must always be kind to and tolerant of others.
If you're often angry, that's a big clue that something needs to be investigated. What is making you angry? You need to understand the source of your reaction. Do consider how you react. People can get into trouble by expressing their anger in harmful ways - to themselves or to others.
But you can also damage your health if you always bury your anger. It's best to identify why you feel that way.
The past is over - unless you're replaying history repeatedly. If that's the case (and it isn't something of a legal nature), sit with the original event, notice why you felt powerless at that time and then bring in your current knowledge and wisdom. You're a different person now, so why are you stuck in the past? This is an indication that something hasn't been healed.
If someone's bad behavior is current, first note that you have options. Brainstorm the possibilities, even if they take time to complete.
Concentrate on transforming your anger into ideas.
If you need to heal old wounds, do the inner work.
If you need to reduce contact with a family member or acquaintance, do it.
If you need to learn how to tell people you feel offended or left out, do it.
If you need to learn that your feelings matter, do it.
If you need to find a job where you feel more respected, do it.
Your life is being affected by your anger. Give yourself time, but keep searching and acting on information that will help you safely and respectfully handle other people's bad behavior. Remember that your handling of these matters comes from within.
Ultimately, getting to know ourself at our core and strengthening ourself within is the solution to much of what ails all of us.