It seems like a century ago that “Minesweeper”—the desktop videogame about avoiding mines—was the universal symbol for procrastination. As of this writing, we have Facebook, Instagram, Twitter, shopping apps, and a thousand other options for that moment when our brain tires of whatever it happens to be working on. The mind does need distractions, but if we’re not careful it’s easy to fritter away an entire workday, working at such an excruciatingly slow pace that we end up exhausted in spi...