I have two that go hand in hand. One cannot exist without the other in my moral compass.
Acceptance and resistance.
Accept the things you truly cannot change and resist the injustices/cruelties that you can take a stand for and help to change.
Took me a hell of a long time to learn to accept certain things as absolutes, like the fact that suffering is an inherent part of life, but I have always been one to fight against things that can be changed. Not all suffering should be inherent to the human experience, though, and a lot of it can be fought against.
Every day I the thought that I’ll never retire becomes closer to reality. My IRA is only 2 years old. I can’t bring myself to check on it because I expect it to be gone. I’ll just let the dude who manages it stress over the details while I stress over the big picture.