The tricky thing about writing shorter works is there is much less time to make an overall good impression. A novel's plot is an intricate weave of multiple plots, characters and themes.
In other words, lots of time to create a favorable impression. It's not quite so vitally important for the reader to like every character. So long as they like enough of what is going on, it's a satisfying reading experience.
What one person finds "satisfying"may be unsatisfying for another. Therefore, a short story writer must be extremely clear about what type of reader the story is trying to appeal to. If it's horror, the focus should be building that fear. If it's science fiction, the focus should be on world-building.
Instant draw. Instant connection.