When you make love you’re using up energy; and afterwards you feel happy and don’t give a damn for anything. They can’t bear you to feel like that. They want you to be bursting with energy all the time. All this marching up and down and cheering and waving flags is simply sex gone sour.
– George Orwell
1984. Part 2, Chapter 3. Julia to Wilson, on why the Party is so keen on restricting and controlling sex.