There are two wrong reactions to a rejection slip: deciding it's a final judgment on your story and/or talent, and deciding it's no judgment on your story and/or talent.
Nancy KressChangers are characters who alter in significant ways as a result of the events of your story. They learn something or grow into better or worse people, but by the end of the story they are not the same personalities they were in the beginning. Their change, in its various stages, is called the story's emotional arc.
Nancy Kress