1.20 Explain how ‘worrying about mere possibilities while ignoring probabilities’ can result in people making decisions that not only fail to satisfy social interest, but also fail to satisfy self-interest. Why We Worry About the Things We Shouldn’t . . . and Ignore the Things We Should We pride ourselves on being the only species that understands the concept of risk, yet we have a confounding habit of worrying about mere possibilities while ignoring probabilities, building barricades against perceived dangers while leaving ourselves exposed to real ones: 20 per cent of all adults still smoke; nearly 20 per cent of drivers and more than 30 per cent of backseat passengers don’t use seat belts; two-thirds of us are overweight or obese. We dash across the street against the light and build our homes in flood prone areas – and when they’re demolished by a storm, we rebuild in the same spot.