Explanation: Roman Emperor Marcus Aurelius was a famed (if orthodox) adherent of the Greek philosophical school of Stoicism, and his Meditations are widely read even today both for their wisdom, and their historical insight into the reasoning of Classical philosophy.
Stoicism's core precept, by the way, is that you yourself control your emotions, reactions, and thoughts, and so all pain is self-inflicted, in a very real sense. Bad things happen, yes, but you choose how to react to them. You choose to suffer. The way to happiness? Choosing not to suffer, regardless of circumstances.
While in-practice, the advice lent by Marcus Aurelius in his Meditations is closer to "Take a deep breath, accept that something shitty has happened, and accept that tormenting yourself over it won't change it", that the basic philosophical idea is "It's all in your head, get over it" certainly lends itself to humorous scenarios when taken to the logical extreme.