Being short does not make the story slight. Its length is decided by what one has to say, while the interest never flags. The theme of the story must be integral to the story. It would be impossible to separate the two. The story must go deep into the psyche of the characters.
Regional flavor adds to the effect.
You can't cut characters off from their society. Here it is that conversational style, dress, manners etc become very significant. Observe the world around. These are the very stuff out of which ideas emerge, characters evolve. The writer's business is to contemplate experience, not be merged into it.