It's also rich on subtexts and allegory, if you like. City vs island, intellectual vs primitive, corruption vs integrity, where the shark, white as it is, can be used as a canvas on which we can paint our own meaning. It's also somethink like the revenge of the nerds, as neither Brody nor Hooper (Richard Dreyfuss) are particularly manly or heroic, but actually rather, well, nerdy.
And then there's Quint (Robert Shaw) telling the story of the sinking of U.S.S. Indianapolis. Maybe the shark is sent as revenge for the sins committed during World War 2: