Confirmation Bias

is the general tendency to pay attention to information that supports your conclusions and ignore information that doesn't.

Paying attention to disconfirming evidence is not easy -- it means searching for reasons you might be wrong, and who likes to be wrong?

"Flat Earthers" are dramatic examples for the same. Even after participating in an experiment to prove the earth is flat , their findings concluded otherwise. The result: they said that they were not willing to accept it, and started finding ways to disprove it. 

Being aware to confirmation bais can pay dividents and prevent major errors.