Let's just say the directing was great, the writing was great, the shark was great, Scheider and Dreyfuss were great, John Williams ' score was great, and Mr Shaw was perfectly cast (pardon the pun).
Oh, and the boat was great, even though in the movie a bigger boat was requested by Mr Scheider.
In AFI's 100 most thrilling films JAWS placed second behind Hitchcock's PSYCHO.