I honestly think people take it way too seriously and apply it too generally. Quantifying "good" is hard if you don't know much about the field you're quantifying. Getting deep into a particular field is humbling -- Tetris seems relatively simple, but there are people who could fill a book with things _I_ don't know about it, despite playing at least a few hundred hours of it.
Is there an answer to that humility gained by being an expert in one field being translated to better self-assessment in other fields? I feel myself further appreciating the depth and complexity of fields I "wrote off" as trivial and uninteresting when I was younger as I get deeper into my own field (and see just how much deeper it is too).