This might be more about self-deceit, but it still addresses good / bad. The most recent emission from Robert Genn:

"Christopher Foyle, British owner of Foyle's Bookshops, has recently published "Foyle's Philavery: A Treasury of Unusual Words." In it he defines arcane English words currently dropped or seldom used. Among them "Dentiloquy" (speaking through clenched teeth) and "Latrability" (the ability to bark). Many words have sly connections with art. One in particular needs to be returned to mainline usage:

"Kalopsia" is the condition in which things appear more beautiful than they really are. It's like where girls (and boys) in bars, for example, tend to look more attractive nearer to closing time. For example: "At 11pm the bar was high on kalopsia."

Kalopsia also applies to regular people and self-deluding artists who just can't see how bad certain art really is. As in the bar, there are pressures to overlook problems in the name of expediency. In the real world, artists with a high degree of kalopsia can remain wallflowers unless they go for the cure.

When self-esteem is low, artists tend to give themselves a premature pat on the back. We all know of artists who are forever in a state of euphoric bliss about their essentially crummy art. These folks may rationalize that joy itself is
enough, but it isn't. Pleasing yourself is loaded with potential self-deceit. The problem is compounded when an occasional observer says it's good stuff. Worse still, people can start to believe in the delusion of a perpetrator--a widespread, contagious human condition.

What's the cure? It certainly helps to know how truly excellent work can be. Seeing, appreciating and understanding competence sets higher personal goals and spurs both imagination and facility. A sense of experimentation in the studio and the application of honest doubt are healthy for growth and mastery. Good enough is never good enough. Putting in that extra thought and effort--without overworking--is key. Further, it's important not to get derailed by trend, story or hype. Everyone, particularly artists, should remember that no matter how good the story, quality still counts. The world is fully loaded with folks who are content with mediocrity. Evolved artists simply won't let themselves be one of them."