The ancient Greeks were great storytellers. They were also deeply religious. They believed their gods and goddesses and other magical beings really existed. They believed these magical beings could interfere in their lives, to help them or to hurt them.
The ancient Greeks built temples to honor their major gods. Each temple honored only one god. So there were many, many temples in ancient Greece.
The ancient Greeks told stories about their gods. These stories are called myths (short for mythology, or stories about gods.) The thing about myths is that the gods' adventures might change, depending upon the storyteller, but the personalities and powers of the gods remained consistent. Zeus was always the king of all the gods. His wife, Hera, was always jealous. Poseidon, his brother, always ruled the sea. His other brother, Hades, always ruled the Underworld. His sister Demeter ruled the harvest. Hestia, his other sister, ruled the home. Their kids had jobs, too. Everybody in ancient Greece had jobs, including the gods.
All the gods had magical powers, although not all the gods had the same powers. Whatever powers they had were consistent from story to story, because the Greeks knew their gods well. For example, Zeus and only Zeus could throw lightning bolts. Some gods could shape-shift and turn themselves into animals, humans, whatever they wanted. What was not consistent was the story itself. Some stories had several different endings or beginning or middles. The gods remained the same but the story did not always.
For example, by now you know the story of the monster in the maze on the island of Crete. On that much, storytellers agree. But some storytellers made the maze above ground, with very high impenetrable walls created from twisted sharp olive branches, with an open top so the monster could be heard bellowing. Some storytellers place the maze underground, where the monster would never see the light of day. Still others positioned the maze as partly underground and partly above ground. It all depended on the storyteller. But all the storytellers agree that the monster had a head like a bull with horn and the body of a man. Consistent, yet not. Confusing? That's the Greeks for you. Always creative.
It's important to remember that a myth is not real - it's just a story. The ancient Greeks believed in their gods. They enjoyed the stories, stories about a mystical world full of bickering and fights and wars and compromise and fear and fun and punishment and love. Many myths were based on the fact that gods, like mortal men, could be punished or rewarded for their actions.
One of my college professors told me once to think of the Greek myths as ancient gossip. The ancient Greeks were always eager to hear what their gods were up to now, and the storytellers were always glad to tell them, in exchange for food, clothing, and a warm place to sleep. The more I think about it, the more I believe he was absolutely spot on.