This is a great question. Edward Sissorhands is a remarkable movie that exposes the human heart in a very clever way.
The protagonist of the movie is a boy, Edward, whose creator died before completing him. So, he has scissors for hands. One day a woman named Pegg Boggs found him alone in a house. When she found him to be kind and harmless, she brought him home to live with her. In time, people began to meet him. Some wanted to help him; other wanted to use him. Those who wanted to help him have good hearts, such as Peg and her daughter Kim. Those who wanted to use him for their own gain or simply hated him have evil hearts, such as Esmerelda, Jim, and Joyce.
Here are two scenes.
First, Peg takes him into her home in the beginning of the movie. Why would should do that? It is only because of the goodness of her heart. Also at the end of the movie, we realize that the narrator is actually Kim, who had fallen in love with Edward. This shows a love that is deep.
Second, when Jim finds that Edward's hands can successfully pick locks, Jim feigns friendship only to use him to rob places. And in the end, when they are caught, he shifts the blame onto Edward alone. This show the base nature of humans.
The movie is clever, because all the characters are introduced to the same creation, Edward, but they all act differently. What is different in their nature? Some have good natures that want to help him and have compassion for him; other have selfish, jealous, or even hateful natures, and they act accordingly. A good tree produces good fruits and a bad tree bad fruit.