Anger is the hardest thing to overcome both in the moment and in the midnight recriminations of “by golly, if I’d only said this or that, I’d have shown ‘em,” largely because they overtake the gut biome.
Pay attention to your anger, it upsets your stomach. Creates a pit.
This makes for a great object of meditation. Then the scene of the initial anger resurfaces and you start all over again. The pit is dug deeper.
“A memory being known.”
You are not the memory, you are not the angry scene, you are just consciousness crystallized in a thought.
“A stomach sensation being known.”
This is now. Don’t push it away in aversion. It is transient, it’ll go soon enough. Experience it as long as it persists.
“A memory being known.”
Wake up. Realize that you just arose from a mindless state of being lost in the memory of the anger-inducing incident. Rinse, repeat... as much as is required.
Anger is by far the hardest of mind states to relieve. Go outside, on a run, on a mental health day... you can mindfully reduce the grip of this state on your being.