She said, 'I'm so afraid.' And I said, 'why?,' and she said, 'Because I'm so profoundly happy, Dr. Rasul. Happiness like this is frightening.' I asked her why and she said, 'They only let you be this happy if they're preparing to take something from you.
Khaled Hosseini (2004). “The Kite Runner”, p.188, Penguin