is it possible for a piece of #writing advice to be both the best and the worst?

i feel this way about 'show, don't tell.' when i first learned about this rule (back in high school) it was a big 'aha' moment for me. but the more high quality books i read (literary classics, Nobel or Pulitzer winners etc.) the more i realized that great writers both show and tell all the time. they're just really good at both skills, and they know when to use them judiciously.