To think that the spectre you see is an illusion does not rob him of his terrors: it simply adds the further terror of madness itself -- and then on top of that the horrible surmise that those whom the rest call mad have, all along, been the only people who see the world as it really is.
What you see and hear depends a good deal on where you are standing; it also depends on what sort of person you are.
C.S. LEWIS, The Magician's Nephew
Sanity ... had it ever been more than a convention -- a comfortable set of blinkers, an agreed mode of wishful thinking, which excluded from our view the full strangeness and malevolence of the universe we are compelled to inhabit?
I can imagine no man who will look with more horror on the End than a conscientious revolutionary who has, in a sense sincerely, been justifying cruelties and injustices inflicted on millions of his contemporaries by the benefits which he hopes to confer on future generations: generations who, as one terrible moment now reveals to him, were never going to exist. Then he will see the massacres, the faked trials, the deportations, to be all ineffaceably real, an essential part, his part, in the drama that has just ended: while the future Utopia had never been anything but a fantasy.
C.S. LEWIS, The World's Last Night
As long as what you are afraid of is something evil, you may still hope that the good may come to your rescue. But suppose you struggle through to the good and find that it also is dreadful? How if food itself turns out to be the very thing you can't eat, and home the very place you can't live, and your very comforter the person who makes you uncomfortable? Then, indeed, there is no rescue possible: the last card has been played.