Why dou think the same themes recur in folk tales from different countries?

Each folk tale contains an evil, a scary, a good, and a "father-role" character, a hero and/or a heroine. These tales represent the life, and these characters are not people, but the different types of good or bad forces in the life. In the most tales of the world, witches, dragons, fairies, magical animals/plants, magitians and kings appear. Dragons are the scary character, representing the terrible problems in your life, with which you have to deal, you have to solve tese (no hero dies in the fight of a dragon). Witches, magicians, and fairies represent the the forces or people who want to help or block you. The characters who can have father-role are obviously the father of the hero, the king, the shepherd, or God. They represent the divine caring, the love and goodness, sometimes fathers, kings or shepherds have divine power, and they are mystic. And obviously there is the goal of your life: the beautiful princess.