'Shark Tank' investor Robert Herjavec reveals how deals are affected by what happens behind the scenes

"Shark Tank"/ABC When "Shark Tank" returns on Sept. 23 for its Season 8 premiere, millions of Americans will tune in to watch a reality show with real stakes, where entrepreneurs pitch their companies to a panel of investors who can potentially change their lives. A great product and charisma are necessary for a deal, but a bit of luck is involved as well, since the Sharks' moods are closely tied to their shooting schedule, cast member Robert Herjavec reveals in his latest book, "You Don't Have ...