[I]n other words, we should live with due knowledge of the…

““[I]n other words, we should live with due knowledge of the course of things in the world. For whenever a man in any way loses self-control, or is struck down by a misfortune, grows angry, or loses heart, he shows in this way that he finds things different from what he expected, and consequently that he laboured under a mistake, did not know the world and life, did not know how at every step the will of the individual is crossed and thwarted by the chance of inanimate nature, by contrary aims and intentions, even by the malice inspired in others. Therefore either he has not used his reason to arrive at a general knowledge of this characteristic of life, or he lacks the power of judgement, when he does not again recognize in the particular what he knows in general, and when he is therefore surprised by it and loses his self-control. Thus every keen pleasure is an error, an illusion, since no attained wish can permanently satisfy, and also because every possession and every happiness is only lent by chance for an indefinite time, and can therefore be demanded back in the next hour. Thus both originate from defective knowledge. Therefore the wise man always holds himself aloof from jubilation and sorrow, and no event disturbs his ἀταραξία [ataraxia]." —from_The World as Will and Representation_. Translated from the German by E. F. J. Paye in two volumes: volume I, p. 88””

— Arthur Schopenhauer