Memento Mori refers to the philosophical reminder of death’s inevitability. You could leave life right now. Let that determine what you do and say and think. It helps you remember the good things without arrogance and to let the bad things go with indifference. You control whether you waste time getting upset by things. And whether you waste time taking things personally.

Amor fati is a phrase that may be translated as “love of one’s fate”. It is used to describe an attitude in which one sees everything that happens in one’s life, including suffering and loss, as good or, at the very least, necessary. You take what you can from life. You use it as fuel. You become better from it. You become improved by it. Make the most of it. Be better for it having happened.

Nobel prize–winner and game theory pioneer Reinhard Selten observed that people work diligently to be rational ex post. That is, we commonly look back at how a situation played out to try and understand how a better outcome might have been achieved. This contrasts with a game theory approach in which the goal is to develop a strategy that will lead to that better outcome a priori.