There is only one inborn erroneous notion … that we exist in order to be happy … So long as we persist in this inborn error … the world seems to us full of contradictions. For at every step, in great things and small, we are bound to experience that the world and life are certainly not arranged for the purpose of maintaining a happy existence … hence the countenances of almost all elderly persons wear the expression of … disappointment.

Vol II "On the Road to Salvation" - The World as Will and Representation (1819; 1844)