Mind Meld: What Makes the Perfect Short Story?

I recently participated in another Mind Meld at the SFSignal website with about 20 other writers and editors. This was the question posed by superfan Paul Weimer, which each of us answered in our own way:

Novels have to do many things, novellas a few things. But a short story is a pure, distilled idea, crystallized down to the core, drilling down through a reader’s shields and evoking a reaction, branding a reader’s memory forever. With this in mind, we asked our contributors:
Q: What do you consider the perfect SF/F short story, or the elements of one?

Follow the link at http://www.sfsignal.com/archives/2015/12/mind-meld-makes-perfect-short-story/ and scroll down to see my reply along with those of many others.

(This item was really published here on Dec. 19 but scheduled as if on Dec. 16, the day the Mind Meld went up at SFSignal, to keep my essays chronologically tidy in my blog's timeline.)