The clap-clap of the water

 "You may have noticed that the books you really love are bound together by a secret thread. You know very well what is the common quality that makes you love them, though you cannot put it into words: but most of your friends do not see it at all. Again, you have stood before some landscape, which seems to embody what you've been looking for all your life. Even in your hobbies, has there not always been some secret attraction which the others are curiously ignorant of - something, not to be identified with, but always on the verge of breaking through, the smell of cut wood in the workshop or the clap-clap of water against the boat's side. Are not all lifelong friendships born at the moment when at last you meet another human being who has some inkling of that something which you were born desiring, and which, beneath the flux of other desires and in all the momentary silences between the louder passions, night and day, year by year, from childhood to old age, you are looking for, watching for, listening for?" 

-C.S. Lewis, The Problem of Pain 1940