Greek and Roman mythology was born because people were curious to know about the root of their existence: how they came to the world, and everything that surrounds them. It was born during the time of no scientific advancement. The unexplained world gave a reason to fear and to behave. They worshipped many Gods, creating a polytheistic society. They believed that the Gods controlled natural forces. Roman mythology is a combination of rituals, beliefs, and supernatural occurrences. The Romans adopted most Greek gods and their tales, and only changed the name.
I believe that the gods and goddesses from the myths represent human nature: they get jealous, angry, and sometimes mislead by greed. They fight over women; they are even involved in infidelity. Again, they possess supernatural power; the only aspect that separates them from human. I think it's also an expression of human beings desire to have control over each other. Among all the figures of the mythology, the character that I think is more relevant to me is Zeus. He is king of all gods and father of human beings. His actions represent human nature most effectively.
The first aspect of Zeus' character that draws everyone attention, I think, is dominance. He established himself as the king of all gods. It didn't come to him naturally. He had to fight with his father, Cronus, and with other Titan gods. Cronus, who used to rule the world during the Golden Age, also had to kill his own father, Uranus. Cronus had an oracle that one of his sons would overthrow him as he had done to his father. To insure his realm, he started swallowing his own offspring until Rhea tricked him during the birth of Zeus. When Zeus grew up, he along with his other siblings, defeated the Titans and imprisoned them to Tartarus. The conflicts between Zeus and Cronus for establishing dominance and securing power symbolize men's hunger for control. These incidences have been taking place since the beginning of human civilization. The greed for power has given rise to jealousy, trickery, swindle, deceit, and has increased the necessity for strict laws.
However, I think the most interesting feature of Zeus' character is that he is a womanizer. He is married to the goddess Hera. But he still made relationship not only with other goddesses...