Sooner or later in life everyone discovers that perfect happiness is unrealizable, but there are few who pause to consider the antithesis: that perfect unhappiness is equally unattainable. 

Human nature is such that grief and pain — even simultaneously suffered — do not add up as a whole in our consciousness, but hide, the lesser behind the greater, according to a definite law of perspective… This is the reason why … man is never content. In fact it is not a question of a human incapacity for a state of absolute happiness, but of an ever-insufficient knowledge of the complex nature of the state of unhappiness; so that the single name of the major cause is given to all its causes, which are composite and set out in an order of urgency. And if the most immediate cause of stress comes to an end, you are grievously amazed to see that another one lies behind; and in reality a whole series of others.