People who work or have worked in customer service, what has a customer said that made you think “people cant get dumber than this”?

A cute example is my little sister going “Pasta with sauce but without sauce” because as a toddler you dont quite get how food works

A real example is me working at an Oktoberfest-themed event , as a German, and a customer insisting that I couldnt be German cause no German would work at an Oktoberfest.

Was an out of body experience really, even after switching to German, the English speaking person still persisted that I could in no way shape or form be authentic.