" Then these moments of perplexity began to recur oftener and oftener, and always in the same form. They were always expressed by the questions: What is it for? What does it lead to? At first it seemed to me that these were aimless and irrelevant questions. I thought that it was all well known, and that if I should ever wish to deal with the solution it would not cost me much effort; just at present I had no time for it, but when I wanted to I should be able to find the answer. The questions however began to repeat themselves frequently, and to demand replies more and more insistently; and like drops of ink always falling on one place they ran together into one black blot. Then occurred what happens to everyone sickening with a mortal internal disease. At first trivial signs of indisposition appear to which the sick man pays no attention; then these signs reappear more and more often and merge into one uninterrupted period of suffering. The suffering increases, and before the sick man can look round, what he took for a mere indisposition has already become more important to him than anything else in the world -- it is death! That is what happened to me. "

― Leo Tolstoy , A Confession