Re, what makes a short story compelling:
To be honest, the thing that first drew me to short stories was their literal brevity. When I was younger -- like, teenager into early 20s -- there was this sourceless, vague sense that I was supposed to Get Books on a Deep Level and Have Smart Thoughts About Them. And also this (again, sourceless and vague) sense that I was wasting my life if I didn't read at all, and (perceived) pressure to Read All the Recommended Things. I think that kind of anxiety exists for a lot of people who got good grades when they were a kid. You know, that "what if I'm unable to do anymore what I think people expect me to do and then I look stupid and people think I have no more worth" feeling.
Short stories were nice because they were digestible. I could read one quickly, minimizing the amount of time I spent feeling anxious that I wasn't Thinking Hard Enough, but still feel afterward that I had made some progress toward Being More Well-Read. They also give you quick exposure to a lot of different authors, if you're reading a variety anthology instead of a single-author collection. That made me feel a little better as well, like I was covering more ground that way. If anybody asked me if I had read Heinlein, I could say, "Oh yes, that one short story he had in The Best of Fantasy and Science Fiction Vol 1." Even if I couldn't have a smart conversation about it, at least I felt like I was In the Club. But still, that fear of not measuring up, not looking smart enough, the fear of feeling dumb while reading something that was supposed to be inspiring and impactful, poisoned how I read/thought about books for a long, long time.
(Wow, even just writing this reflection makes my chest tighten with stress.)
I still really appreciate the brevity and breadth of a collection of short stories, and would rather have a volume of short stories than any single-story book. A single short story, shared between people, is so much easier to sit down and read than a recommended book, so it lends itself to sharing. And a good short story has such a thematic purity to it -- instead of a piece of music, which a longer work of prose might be, the skillfully-written short story is a struck bell, or pair or trio of bells. Direct, clear in its vision (even if its final message is ambiguous, a la Turn of the Screw, which was wonderful), impactful. The poetry of stories.
I felt this way when somebody shared that Ursula K LeGuin short story in the Lovely People thread -- it struck straight to the heart of what it was saying by the end, and had at least two main facets that I kept going back and forth between.
It's very interesting to me, Songbird, that the thing you like is how a larger world can be hinted at by a short story without needing to be explored -- and Sc0ut, you've said something similar, that the lack of descriptive detail allows you to fill in the gaps in the setting yourself. The sense that I'm looking at just a piece of something larger/incomplete often bothers me, possibly because of that old fear of Not Getting the Whole Picture and not being smart enough to see it. But the way you talk about it, it makes a short story seem sort of floaty and gauzy, you know, a delicate shred wafting gently on a broad, undefined wind. (I don't really know how to describe it better than that, sorry, that's just how it looks in my head.) I would like to be able to appreciate that aspect of short stories someday.