Show, don't tell. Never use incomplete sentences. Two rules of fiction writing, or advice we are told to take to heart, I am uncomfortable with. Sometimes, I think many times, telling is the better choice than showing. But this depends on your confidence as a writer, and how you wish to say what you have to say. I've seen telling used effectively by many writers. I like to challenge myself as a writer, and as a reader, to imagine what the writer sees, rather then have it spelled out for me. Perhaps, the rule may be better stated Show don't tell, but not all the time. Regarding incomplete sentences, I appreciate authors who use them. Not a lot of the time, but some of the time. Where a particular mood is desired, and where that mood is clearly understood in the context of what is happening. Or whether you want the action to be quickly paced. In summary, these are two, but only two, rules of fiction writing that the author can, from time to time break. Without him, or her, being accused of bad or slipshod writing.
Stories that don't necessarily follow the norms of fiction, whatever they are. Stories that may always be tied to the rules of literature, but are accepted forms of literature. There are authors who choose to craft their fiction in this manner. Some of these authors are William Faulkner, Charles Dickens, Ernest Hemingway, Virginia Wolf, James Joyce, Cormack McCarthy, Marcel Proust, Samuel Becket, Fyodor Dostoevsky. And the imaginative, and highly experimental, fiction of Mark J. Danielewski. No one would call these authors limited in what they do. It is okay, in some cases, to break from the rules of fiction to follow your own way.
I'd say that "show don't tell" isn't a sufficiently clear directive to allow anyone to know for sure if you're breaking it or not.
