Sometimes you’ll get a new book, glance through a few chapters, put it on the coffee table for later indulgence, and get back to whatever you were doing. You don’t have time to actually read your new book yet. You've got a lot of work to do, and you're already part way through a couple other ones, so it’ll have to wait.
But then a strange thing happens: Over the next couple weeks, you've done it again. You've bought another must-have book, and the last book, the one that was waiting for you on the coffee table, has silently migrated to your bookshelf, without ever getting read.