Mom and Dad had finally arrived from their honeymoon, and both children ran over to hug them and bring their bags in. Afterwards, they had long, joyful talks about their trips. Then they decided to watch a scary movie together.

The lights in the sitting room were turned off for maximum effect. The parents chose to sit on a thick blanket that had been laid earlier on the tiled floor, and then they huddled together, sharing one big bowl of popcorn. Behind them was the couch, and their kids sat on ...