What are some of the reasons annabeth gives for why poseidon and Athena do not get along?

Annabeth explains that Poseidon and Athena do not get along due to a rivalry over Athens, as they both wanted to be the city's patron god or goddess. Additionally, their differing domains - Poseidon being the god of the sea and Athena being the goddess of wisdom and war - also contribute to their discord. Their competitive natures and conflicting personalities further fuel their animosity towards each other.