C

“The best thing for being sad," replied Merlin, beginning to puff and blow, "is to learn something. That's the only thing that never fails. You may grow old and trembling in your anatomies, you may lie awake at night listening to the disorder of your veins, you may miss your only love, you may see the world about you devastated by evil lunatics, or know your honour trampled in the sewers of baser minds. There is only one thing for it then — to learn. Learn why the world wags and what wags it. That is the only thing which the mind can never exhaust, never alienate, never be tortured by, never fear or distrust, and never dream of regretting. Learning is the only thing for you. Look what a lot of things there are to learn.”
― T.H. White, The Once and Future King

“Totally without hope one cannot live. To live without hope is to cease to live. Hell is hopelessness. It is no accident that above the entrance to Dante's hell is the inscription: "Leave behind all hope, you who enter here.”
― Jurgen Moltmann, Theology of Hope: On the Ground and the Implications of a Christian Eschatology

“Life, although it may only be an accumulation of anguish, is dear to me, and I will defend it.”
― Mary Shelley, Frankenstein

“I don't know why we are here, but I'm pretty sure that it is not in order to enjoy ourselves.”
― Ludwig Wittgenstein