" Here’s what’s uniquely insidious about caffeine: the drug is not only a leading cause of our sleep deprivation; it is also the principal tool we rely on to remedy the problem. Most of the caffeine consumed today is being used to compensate for the lousy sleep that caffeine causes. Which means that caffeine is helping to hide from our awareness the very problem that caffeine creates. Charles Czeisler, an expert on sleep and circadian rhythms at Harvard Medical School, put the matter starkly several years ago in a National Geographic article by T. R. Reid: The principal reason that caffeine is used around the world is to promote wakefulness. But the principal reason that people need that crutch is inadequate sleep. Think about that: We use caffeine to make up for a sleep deficit that is largely the result of using caffeine. "

― Michael Pollan , This Is Your Mind on Plants