Normalcy bias
Normalcy bias is assuming that because a disaster has never happened to you, it won't happen, and underestimating how bad it could be if it does. It can make people slow to respond to clear warnings.
In everyday life
Residents ignore an evacuation order for a hurricane because past storms in their area turned out mild.
When the fire alarm sounds during a movie and staff tell everyone to leave, you stay in your seat, sure nothing serious could happen on an ordinary Friday night out.
Why your mind does this
Our brains handle small, concrete quantities well but struggle with large numbers, fractions and odds. Rounding, grouping and labeling let us make fast decisions without doing the math. For most daily choices, a rough answer is good enough.
Its family, in 30 seconds: Simpler numbers
How to spot it
Notice when your main reason for ignoring a warning is 'it's never happened before'.
How to counter it
Make a simple emergency plan in advance, so that acting on a warning becomes automatic.
Same family: Simpler numbers
SourcesOmer & Alon (1994)·Wikipedia