The Back Story of Every Last Character

When a television show becomes successful, producers begin to develop the back story of every last character. They do that again and again and again to fill in the plot that hooked you in the first place. You're not just cheering on the hero, but you are deeply invested in the life story of each member,. even of the periphery cast. Suddenly every character matters to you, and every scene is an important one. And they've got you.