Brandon Sanderson said this quote

By now, it is probably very late at night, and you have stayed up to read this book when you should have gone to sleep. If this is the case, then I commend you for falling into my trap. It is a writer's greatest pleasure to hear that someone was kept up until the unholy hours of the morning reading one of his books. It goes back to authors being terrible people who delight in the suffering of others. Plus, we get a kickback from the caffeine industry...