Acknowledge that bad things happen, lies are told, and people misbehave. These are facts not in dispute.
However, if you have time to list grudges and folks who’ve done you wrong, you might have too much free time.
Find something that occupies you so completely, so creatively, that you have no time for counting grievances.
Live life forward.
Find new challenges.
Escape the grasp of those who seek to keep you from excellence.
Live so they don’t matter.