Optimism Bias

The tendency to believe that one is less likely to experience negative events and more likely to experience positive events.

A couple getting married believes their marriage will be different from the 40-50% that end in divorce, despite having no particular reason to expect better odds. They underestimate their personal probability of divorce compared to the statistical base rate.
A driver who texts occasionally while driving believes they won't have an accident because they're "careful," even though texting drivers have significantly elevated crash risk. Personal optimism discounts actual risk factors.

Note

Extensively researched by Tali Sharot, whose work has illuminated both the neural mechanisms underlying optimism bias and its adaptive functions.

This is a common bias