The benefits good people provide in our lives are varied and obvious. They're kind, loving, and compassionate. They teach us to be grateful for the support and generosity we receive from loved ones, especially during difficult times. Now what about bad people -- the selfish, narcissistic, dishonest, insensitive, opportunistic individuals we come across every now and then? Do they benefit us in any way? Absolutely. Like the good people, they teach us a valuable lesson: Whom not to associate with. They demonstrate the opposite qualities we should strive to develop and nurture ourselves, seek in other people, and instill in our children. They embody precisely the kind of person we should aim to avoid because, rather than enhance our lives like the good people do, they diminish them with their pride, self-absorption, and callousness. Granted, nobody's perfect. We all exhibit shades of selfishness here and there. We all fib on occasion. But some people take it to a who...