As a reader, one thing that bothers me about some critics is their presumption of an artist's intentions and their then attacking that artist for what they have presumed. Let's say an artist creates an original theater piece or stages an extant piece or choreographs a known score/scenario or paints a picture or writes a book. The critic presumes to know that the artist doesn't really truly sincerely believe in the material at hand, and is thus cynically or frivolously blowing it off, and hence can be attacked for insincerity or mendaciousness.
The trouble is, what if the artist does indeed turly sincerely believe in what he or she is doing. Then what? The critic may still feel free to dislike what he/she sees, but the entire conceit of blaming the artist for manipulative insincerity collapses on a false premise, yet the innocent reader has no idea that the critic's presumption was incorrect.
My complaint is not to be confused with that old saw artists sometimes play, wherein the critic is criticised for not accepting or understanding the terms on which the artist was working. In my recent experience, this complaint becomes especially acute in experimental dance, which almost invariably comes freighted with explanatory verbiage impenetrable in its vacuousness and pomposity. The critic has every right to judge a work on his (or her; political correctness can be BORING) terms, but not to presume a knowledge of the artist's terms when he doesn't really know them at all.
This is turn leads to the hoary issue of how close a critic should be to an artist, and hence how boldly he may assume knowledge of the artist's intentions on the basis of intense discussion and close observation of the artist at work. In a sense, we're all mysterious; we don't even know our own motives. So any presumption of another's intentions, even after close contact, may be illusory. And close contact invites all manner of social awkwardness and perceived or actual conflicts of interest that vitiate whatever insight may have been gained.
I am no formalist critic, determined to parse the text free of all encumbering historical or psychological context. Context -- temporal, cultural, personal -- is important, crucial. It's just that there are presumptuous bounds one can overstep, and one should try one's very best not to do that.