Most people are more optimistic than would be epistemically rational; they systematically underestimate the risks and overestimate their abilities. However, this kind of bias may be instrumentally useful: it makes people do things, even if most of the things will not bring the outcome they imagine. Because of some quirks of human brain, people who perceive reality better often have problem to motivate themselves. This hypothesis is called depressive realism.
But I believe that is just a part of the story, and maybe the less important part. It is the part of the story that fits into the just-world narrative. You get something (precision), you lose something (motivation), the harmony in the universe is restored.
The other part of the story is that better epistemic rationality can bring you some social problems. If your friends are not interested in being epistemically rational, you will feel alone with your thoughts. If you perceive how things can go wrong, and others deny it, of couse you see a danger where they don’t. The danger is real, the helplessness is real (if a larger cooperation is needed to prevent the danger), the feeling of being alone (in your mental landscape) is real.
Story of my life.