Another example is the people in camera groups posting photos on Facebook and talking about the "sharpness" of a lens when Facebook so horribly reduces/destroys the quality and detail of photos to reduce file size, so no way to really evaluate in such a way. Also that most lenses produced over the past 50 years are sharper than human eyes could ever tell differences yet they argue endlessly... just like audio guys. No way to evaluate sound from a YouTube clip, but the banter about the experience of the listeners in the actual room may be valid.