This movie has no physical violence, but it's truly scary. Chad is evil. He hurts others' feelings for the pleasure of showing himself that he can. He has an explanation for his cruelty, but that's just to draw Howard in to play his game. Without that explanation, he'd still find reasons to be cruel, because his pleasure comes from seeing others in pain. Worse, he can get away with his cruelty, because he is charming, charismatic, and effectively manipulative in his dealings with people. Except in the central plot, he manages to hurt people without taking the blame, by making his victims blame themselves.<br /><br />Howard is both a victim and a willing participant in Chad's evil plot. Without people like him, people like Chad are much less able to hurt others. But people who are too weak to stand in the way of bad people are fairly common. Even those weak enough to be drawn into the plots of bad people are common enough. Even a person strong enough to foil Chad's plot could only have done so if he had known about it, and Chad knew not to trust his plans with such a person. Howard had a chance to be the hero, but he was too weak and became another villain.<br /><br />The central victim, Christine, started out suspicious, but was drawn in by Chad's skillful manipulation, and to some extent Howard's real interest in her. Chad was also good at choosing a victim who would fall for the plot, just as he chose an accomplice effectively. Other victims had other weaknesses that Chad found ways of exploiting, like the man whose speech he mocked in a way that made that victim feel like he himself was to blame.<br /><br />Most people have never met a serial killer, but many have met people like Chad, who enjoy hurting others. The fact that Chad is an example of a more familiar type of evil makes him much scarier. He's more chilling because he doesn't have a clear reason for his badness -- he just enjoys being cruel. What is scarier than an evil that one can imagine falling victim to in everyday life?