The show-don't-tell mantra has an interesting saga in a writer's life. Initially, we are all tellers; recall, for example, ghost stories told around the campfire. But then, beginning writers are consistently warned to "show, don't tell" once they start to get educated. As writers progress, however, they learn that some telling is a good thing; it can summarize boring bits, for example. Some writers then complete the circle and return to almost all telling.
I'm here to tell you as genre writers: do not do this. The tradition of genre writing such as fantasy, science fiction, and horror is mostly showing. This means dialogue. This means describe action. When you show, you let the reader experience things as if he/she was the character. When you tell, you impose an additional layer (author) between the character and the reader. The beauty of fiction is it is the only medium is which the reader gets to be someone (something?) else. Don't take that away from the reader!
Telling is less dramatic. Showing is more dramatic.
If I haven't convinced you with my logic, let me say this: we've never had an all telling story make it into the hold-for-voting file here at Electric Spec.
Stay tuned for an exciting new issue at the end of the month!