Perhaps rejection makes him defensive because he seeks to be accepted. He resolves never to have anything to do with her again. In other words, conflicts are the obstacles the main characters must overcome in order to achieve their goals. In a romance, the main goal is for the hero and heroine to fall in love and stay together. In a science fiction story, maybe the goal is to overthrow an evil corporation dominating the planet.
Actions cause reactions.
Whenever you have the chance to put emotion into your synopsis, do it. It makes the difference from a dull summary to a lively recounting of your story. And it is probably the story element used the most. However in your synopsis, you should only include those actions that have consequences. If you heroine takes trip to the store for some eggs, you don't include that unless something happens to her along the way.