And I did nothing, nothing but try to hide from the horror of dying." He stopped, for saying the truth aloud was unendurable. It was not shame that stopped him, but fear, the same fear. He knew now why this tranquil life in sea and sunlight on the rafts seemed to him like an after-life or a dream, unreal. It was because he knew in his heart that reality was empty: without life or warmth or color or sound: without meaning. There were no heights or depths. All this lovely play of form and light and color on the sea and in the eyes of men, was no more than that, a playing of illusions on the shallow void.
Ursula K. Le Guin, The Farthest Shore
depression, ennui