Why is a resolution important to a short story

The resolution is what ties up all the loose ends at the end of a story, such as what happened to a specific character.

The majority of successful works of fiction, whether short or long, tend to have plots based on conflict and resolution. The main exception to this is a genre known as the picaresque, which follows the exploits of a colorful protagonist (a "picaro") through a series of (often comic or adventurous) episodes. Conflict and resolution, and often a desire to see how a conflict will be resolved, are key features which motivate a reader to move through a story from start to finish. They form a structural skeleton around which the edifice of a work is constructed; without this structure, many stories would just ramble on pointlessly.