Answer:
In The Odyssey, Homer writes that Poseidon hated Odysseus, because the Greek hero had blinded, taunted, and made a fool out of the sea god's favorite child, Polyphemus, one of Poseidon's cyclopes children with nymphs.
However, if we take this to a psychological point of view, Poseidon wouldn't have been mad. After all, if you had lots and lots of children, would your favorite be the infamous man-eating, giant, one-eyed monster? Probably not. Perhaps it was in a moment of anger that Poseidon recklessly cursed Odysseus and destroyed his ship and crew.
But Poseidon also, in a twisted way, helped Odysseus. Odysseus washed up on the shores of Ogygia, where Calypso, the immortal daughter of Atlas, was doomed to live forever. Calypso found him and restored him back to help, and like all the other heroes that the Fates have sent to Ogygia, she fell in love with him. Odysseus liked her a bit, too, and stayed there for ten years, before deciding to go home to his family. Penelope was his wife, after all.
And the rules of Ogygia states that when someone wants to leave, a magical wooden raft appears and takes that hero home. So, indirectly, Poseidon did help Odysseus get home.
