As by way of example, their innate cynicism makes them view random acts of kindness as long-awaited miracles. In the normal course of events, John or Elly or whoever expect that everyone is either an enemy devoted to ruining them because they hate them or a witless hindrance blind to the destruction they stupidly visit on our victim heroes. On the rare occasion that they acknowledge that someone has actually done them a good turn out of the goodness of their hearts, they marvel at the miracle of finally being treated the way they deserve.
What the Pattersons lose sight of is that they actually have to set an example of gracious behavior, fair-mindedness and gratitude for minor kindnesses if they expect their children to display said desiderata. Given that John and Elly are entitled swine who can't act like decent people because they feel their imaginary suffering gives them licence to be jerks, I should almost think that maybe being treated like people is a miracle.