"Everyone is a moon, and has a dark side which he never shows to anybody." 
― Mark Twain

"Stars, hide your fires; Let not light see my black and deep desires." 
― William Shakespeare, Macbeth

"I am a forest, and a night of dark trees: but he who is not afraid of my darkness, will find banks full of roses under my cypresses." 
― Friedrich Nietzsche, Thus Spoke Zarathustra

"Into the darkness they go, the wise and the lovely. " 
― Edna St. Vincent Millay

"What makes night within us may leave stars." 
― Victor Hugo, Ninety-Three

"I felt that I breathed an atmosphere of sorrow." 
― Edgar Allan Poe

"Is there no way out of the mind?" 
― Sylvia Plath