Auden, in The Dyer's Hand:
So far as I am concerned, [the critic] can do me one or more of the following services:
- Introduce me to authors or works of which I was hitherto unaware.
- Convince me that I have undervalued an author or a work because I had not read them carefully enough.
- Show me relations between works of different ages and cultures which I could never have seen for myself because I do not know enough and never shall.
- Give a "reading" of a work which increases my understanding of it.
- Throw light upon the process of artistic "Making."
- Throw light upon the relation of art to life, to science, economics, ethics, religion, etc.
Nowadays, in the age of Google and Yelp, we have reviews for everything from candy to music to professors to employers. Everyone's a critic (and everyone's critiqued...). You could easily spend a whole afternoon criticizing everything you spent your morning doing.
Auden says somewhere else that he can't think of a good reason for a critic to spend time reviewing a bad work of art. You might apply the wisdom of Gamaliel: if it's bad, it will fade on its own.
A friend of mine has started personally thanking writers he likes via Twitter. It has become easier and easier to track them down. I once wrote an email to Meghan Daum after reading her essay "Haterade," and got a very lovely and encouraging reply. The distances are small; the Kevin Bacon numbers are low. Don't waste your time. Build each other up.
On the other hand, A. O. Scott argues (in a book, full disclosure, I have not yet read) that art and criticism need one another. That's part of what building each other up means. It's a critic's job to provoke a response, to force articulation, to make people explain why it should be "this way" and not "that way." Because of that, critical opinions are often wrong. And that's what makes them valuable.
In a review of Scott's book, Alissa Wilkinson writes:
Criticism is the art that gives art its lifeblood. Through its form, criticism teaches readers how to look at, read, watch, and listen to art. It takes art seriously. It embraces and champions the undervalued, and it mourns the missed opportunity of the badly made work. Done well, it does not denigrate readers' taste or shame them or dictate their response; rather, it gives them permission to have their own experience with a work of art. Criticism makes order from an unruly world, and it does so through creating something new: "Art criticism is a creative practice, parallel to, not derivative of, the art it addresses," [Daniel] Siedell writes.
If you take art seriously, you should have no problem attacking bad art. Richard Wilbur: "The business of the critic, after all, is to divine the intention of the work, and to interpret the work in the light of that intention..." Someone has to hold us dang artists accountable.
Just be ready to be wrong.