Control the self, not the world. Marcus Aurelius 4.3.4

Our life is properly a series of answers to nature's questions. We are not in charge of what happens, but of how we choose to respond. If we become too invested in dominating what we cannot effectively control, i.e. changes emanating from agency beyond our own, we lose the ability to regulate what is actually within our grasp. Renounce control over the world to gain it over yourself.

λοιπὸν οὖν μέμνησο τῆς ὑποχωρήσεως τῆς εἰς τοῦτο τὸ ἀγρίδιον ἑαυτοῦ καὶ πρὸ παντὸς μὴ σπῶ μηδὲ κατεντείνου, ἀλλὰ ἐλεύθερος ἔσο καὶ ὅρα τὰ πράγματα ὡς ἀνήρ, ὡς ἄνθρωπος, ὡς πολίτης, ὡς θνητὸν ζῷον. ἐν δὲ τοῖς προχειροτάτοις, εἰς ἃ ἐγκύψεις, ταῦτα ἔστω τὰ δύο· ἕν μέν, ὅτι τὰ πράγματα οὐχ ἅπτεται τῆς ψυχῆς, ἀλλ’ ἔξω ἕστηκεν ἀτρεμοῦντα, αἱ δὲ ὀχλήσεις ἐκ μόνης τῆς ἔνδον ὑπολήψεως· ἕτερον δέ, ὅτι πάντα ταῦτα, ὅσα ὁρᾷς, ὅσον οὐδέπω μεταβαλεῖ καὶ οὐκ ἔτι ἔσται· καὶ ὅσων ἤδη μεταβολαῖς αὐτὸς παρατετύχηκας, συνεχῶς διανοοῦ. ὁ κόσμος ἀλλοίωσις, ὁ βίος ὑπόληψις.

From this moment on, remember that you can retreat into yourself, into a private estate that belongs just to you, and do not lust or grasp after anything that comes before you. Remain free instead, and consider affairs dispassionately, as a man, a human, a citizen, and a mortal animal. No matter what circumstances you meet, let two thoughts go with you. First, that your business takes no hold of your soul; it stands beyond the gates of the soul's retreat, incapable of causing any disturbance. All the upheaval you feel comes only from within yourself. Second, that everything you see will cease to exist in time, though you will not be responsible for altering it. Think constantly on the many changes you have witnessed accidently. The universe is a series of changes; life is picking them up.