The knowledge that “this too shall pass”

Knowing you only have a limited amount of energy. I think in terms of a battery - if you have a lot of energy going out (energy can be in many forms - one being stress/worry) and not much going in, this leads to spiraling, fried nerves, impulsiveness, anger etc.

Fill your cup and really focusing on only what you can control - if it’s out of your hands - let it be.