Whatever he does is not only a reward in itself, but will be further rewarded in the sequel; and so pleasure leads on to pleasure in an endless chain.
无论他做什么,事情本身就是一种回报,之后还会带来更多回报;于是快乐引向快乐,连成无尽的链条。
— Robert Louis Stevenson · Virginibus Puerisque, and Other Papers · Walking Tours —