“One rule of thumb is to keep searching for options until you fall in love at least twice. If you’ve only identified one good candidate for a job, for instance, you’ll have the strong urge to talk yourself into hiring her, which is a recipe for the confirmation bias. You’ll start to make excuses for the flaws you see: She asked us not to call her old boss for a reference, but that’s probably okay, because the boss sounded like a real jerk …”