Why were the people of Athens afraid of Poseidon?

The people of Athens were afraid of Poseidon because he was the god of the sea, earthquakes, and horses, and they believed he could unleash destructive forces upon their city. His temperament was unpredictable, and he was known for his wrath when not properly honored. Additionally, the competition between Poseidon and Athena for the patronage of the city heightened their fear, as Poseidon threatened to flood the land or create disasters if he was not favored. Thus, the Athenians sought to appease him to avoid his wrath and ensure their city's safety.