"Good" and "Bad" are irrelevant in the discussion of art. They, like the term "art", are impossible to define in terms of exact definitions or limitations. Every time the words good and bad used, they are implied in different contexts and therefore always have a different meaning. Not to mention the user's background, lifestyle and mindset which forms their personal vocabulary. Together good and bad imply a value range, but the parameters and boundaries of this scale don't exist.
Success is relative, a drawing by a proclaimed artist could look indistinguishable from a drawing that a first grader completed. However, the concept behind the Artists' work would greatly overwhelm that of the child's.
Saying that something is a good work of art is essentially meaningless because good doesn't mean anything without another work to compare it to. Even then, the works could vary in material, style, process and concept so much that a comparison would hardly do either work justice.
I myself am guilty of using these words and I don't think that they should be extinguished from the art world completely for I am a firm believer in positive affirmations and constructive feedback. However I have discovered that in describing something as "good" or "bad" is not specific enough to be informative, helpful or necessary in critique.