hear about random claim from someone in passing.

have absolutely zero evidence to support this claim, but decide it's now a cornerstone of my belief system.

instead of doing something sensible like researching unbiased information to critically analyze the claim, I decide that the best course of action is to only seek out information that confirms my pre-existing belief.

this is because my brain operates on a monkey level of logic and stubbornness. once an idea nestles itself into my grey matter, the mere thought of it being incorrect would shatter my delicate ego into a million pieces. admitting I could be wrong is a fate worse than any cognitive dissonance I might experience.