DEspite America’s reputation for optimism, nearly three-quarters of U.S. adults are pessimistic about the country’s future. [1] This may not be all bad, though. Decades of research have found that positive thinking isn’t always so positive. In some cases, pessimists fare better than those with a sunnier disposition.

Married couples who were extremely optimistic about their relationship’s future were more likely to experience relationship deterioration. [2] Optimism may also be tied to lower earnings. A study of data from British households found that across two decades, especially optimistic self-employed people earned about 25 percent less than their pessimistic peers. [3] And National Cancer Institute researchers found that people who lowballed their risk of heart disease were more likely to show early signs of it. [4]

Maybe this is because a rosy outlook leaves us overconfident. For example, homeowners who underestimated their chances of radon exposure were less likely to buy radon test kits than were those with a more realistic sense of risk—their optimism left them vulnerable. [5]

Optimism can also beget disappointment. In one study, psychology students were surveyed immediately before and after receiving exam results. Students who had anticipated a higher grade than they received were upset after learning their score; students who had underestimated their grade (i.e., the pessimists) felt better afterward. [6]