Take, for example, the so-called “runaway” growth in health care costs. In 2010, conservative deficit hawks called for as much as $1 trillion in cuts to Medicare to prevent an imminent debt crisis. But between 2010 and 2013, CBO’s projections of Medicare spending in the next decade fell by … more than $1 trillion. As Amitabh Chandra, Jonathan Holmes, and Jonathan Skinner wrote in a new paper, the unforeseen slowdown in health-care cost growth wasn’t just the result of the Great Recession. It also came from an increase in high-deductible insurance plans, state efforts to control Medicaid spending, and fewer new, expensive technologies.

As I wrote earlier this year, if all predictions about the future of government spending turn out to be true, it would make sense to treat 10-year forecasts as roadmaps rather than guesswork. But the real world is one where where the most exquisitely delicate change in hospital-costs inflation suddenly saves hundreds of billions of dollars and where factors intervene that fall outside the scope of the Excel sheets that paint these convincing pictures of the future.

You see folks on cable shows and op-ed pages worry about inflation scares, devalued dollars, debilitating health-care cost growth, and debt crises. These are things we think might happen, and we pay attention to these impressionistic projections to the exclusion of things like long-term unemployment and slow job creation—things that we know are actually happening right now.