When I critique my student's artwork I try to be straightforward and not mince my words. I also compliment them frequently in a positive way because I wish to affirm their suspicion that their creative efforts are worthwhile. By complimenting them I am not flattering or pandering, I am validating and supporting their discovery and excitement about making art. So compliments are very useful in that way.
However, even some accomplished artists, who no longer need validation, like to be complimented too, just for having talent, which is a different thing. Compliments make him feel good, even important. It feeds the ego.
The true artist—the artist who is interested in deeper things, will appreciate and enjoy another artist's artwork, but is never impressed because another artist is talented. Neither is he impressed with his own talent, nor depressed by the lack of it. Because he is not interested in personal comparisons. He is only interested in the dynamic creative flow that he is involved in. And he enjoys seeing how that same amazing movement expresses through other artists. His attention is so fully absorbed in that, there is no room for petty comparisons or boasting.
Now, the worst thing a person could say about your artwork is not that it is bad, ugly or amateurish. Surprisingly, comments like that are often very useful, especially if they are thoughtful and informed. And if the work inspires an engaging conversation then that would be an indirect compliment . However, one of the worst thing a person could say to an artists while looking at their art is “Gee, you are so talented! What does it feel like to be so talented? I have no talent whatsoever. I could never do what you do . . . “ In other words, whatever beauty or interest the viewer initially saw in the artwork is instantly obliterated by their ego talking about itself in comparison to another person, the artist. They have completely missed the gift the artist has offered them. On the other hand, one of the best compliments comes without words. It is to observe a viewer's quiet absorption and curiosity as they look at your artwork. In that moment you are watching them experience what you experience as the artist. You want them to experience that same timeless curiosity about the world, without any thought of themselves or another.
Patrick Howe, Artist, Author, Educator, Electronic Music Composer