" It is ludicrous to believe that asset bubbles can only be recognized in hindsight,” he wrote. “There are specific identifiers that are entirely recognizable during the bubble’s inflation. One hallmark of mania is the rapid rise in the incidence and complexity of fraud…. The FBI reports mortgage-related fraud is up fivefold since 2000.” Bad behavior was no longer on the fringes of an otherwise sound economy; it was its central feature. "

― Michael Lewis , The Big Short: Inside the Doomsday Machine