Human life must be some kind of mistake. The truth of this will be sufficiently obvious if we only remember that man is a compound of needs and necessities hard to satisfy; and that even when they are satisfied, all he obtains is a state of painlessness, where nothing remains to him but abandonment to boredom. This is direct proof that existence has no real value in itself; for what is boredom but the feeling of the emptiness of life? If life—the craving for which is the very essence of our being—were possessed of any positive intrinsic value, there would be no such thing as boredom at all: mere existence would satisfy us in itself, and we should want for nothing. But as it is, we take no delight in existence except when we are struggling for something; and then distance and difficulties to be overcome make our goal look as though it would satisfy us—an illusion which vanishes when we reach it; or else when we are occupied with some purely intellectual interest—when in reality we have stepped forth from life to look upon it from the outside, much after the manner of spectators at a play. And even sensual pleasure itself means nothing but a struggle and aspiration, ceasing the moment its aim is attained. Whenever we are not occupied in one of these ways, but cast upon existence itself, its vain and worthless nature is brought home to us; and this is what we mean by boredom. The hankering after what is strange and uncommon—an innate and ineradicable tendency of human nature—shows how glad we are at any interruption of that natural course of affairs which is so very tedious.
From Studies in Pessimism by Arthur Schopenhauer (translation by T. Bailey Saunders).