True story. Last weekend a group of teens gathered in a nicer than average home in the American suburbs to celebrate the fifteenth birthday of a pretty, popular teenage girl. We’ll call her Miranda. Miranda, her mom and her grandma had knocked themselves out for days making tasty food, decorating the pool, deck and house, and devising a hilarious line-up of games and activities. They even had some movie choices to watch before they settled in for the sleepover. Confident she had everything to  keep the girls enjoying themselves for the duration, Miranda’s mom greeted each girl at the door with a promise of great fun and a gentle reminder…