There's a logical fallacy that used to be called "the bad toupee fallacy". It's a kind of bias where you believe the examples you see make up the whole set. Someone may say "toupees are so bad, I can always tell when someone is wearing one." The fallacy is that you only see the bad toupees, the good ones you never notice.
In the 90s professors noticed that students didn't have much experience with spotting toupees (I don't know if toupees fell out of fashion, or if toupee technology has advanced). They now call the fallacy "the bad boob job fallacy".
