Ok, I shall bite (being aware that pertinent answers have already been given).

In my youth, I tacitly assumed that "quality" meant good quality (of any material or immaterial thing), i.e. the word implied a positive value judgment. Later, at work, we had to attend a course in "quality control", and we learned that this means to assure that a product corresponds to specifications, i.e. that it be neither worse nor better than specified (if it were better, this would mean a free gift to the customer). This was quite a change in outlook for me!