"Anybody who reads a lot is, if you like, an addict. The people who put their initials on the fly-leaf of a library copy of a mystery so that they won't keep checking the same book out over and over are story addicts. So is the ten-year-old with his nose in The Hobbit, oblivious to dinnertime or cataclysm. So is the old woman rereading War and Peace for the eighth time. So is the scholar who studies the Odyssey for forty years. The very quality of story is to hold, to fascinate. Ask the Wedding Guest to stop listening once the Ancient Mariner gets going. He can't. He's hooked. Sometimes you get hooked on mere plot, sometimes on mere familiarity and predictability, sometimes you get hooked on great stuff." -- Ursula K. Le Guin, at Book View Café, 2012-06-18
And here's an unrelated but very relevant comic strip.