Why the shark didn't kill Hooper, but did kill Quint and tried to kill Brody
The shark, or Bruce, is obviously not a normal great white. He's much larger and much more intelligent. If my theories right, Bruce is much smarter than it seems.share
In one scene on the boat, after Quint has harpooned 2 buoyancy barrels onto the shark, he is hold rope when it is ragged out of his hands causing such bad rope burn, he bleeds. His hands are hanging over the side of the boat when this happens so it is fair to presume some blood fell into the water. Common knowledge, sharks can sense blood in the water from a few miles away, so if Bruce is a super smart shark and he's so close by at all times he maybe be able to recognize the smell of the blood and link it to Quint.
Considering the shark was willing to kill anything in its vicinity, provoked or not, isn't it unusual it went through the trouble of smashing up the shark cage which contained Hooper, and then ignore his body? He would have had an easy meal right there, but he ignored him and Hooper was able to hide from the shark long enough to surface after it was killed.
Bruce didn't want to kill Hooper because Hooper didn't try to kill it. Although the small harpoons were used before Quints rope burn, the shark may have been smart enough to link the attacks with Quints blood.
Now, say it's nothing to do with blood but with the literal attacks. Quint harpooned him 3 times, and eventually Brody shot him with his own gun a few times before the final scene with the rifle (idk what gun it was, I'm prolly wrong there). In the sharks eyes, Quint was an enemy from the beginning of the boating scene and Brody eventually became an enemy. Before the last 30 or so minutes of the film, when they're on the Orca, the shark doesn't purposely go for anyone in particular: The girl in the beginning was simply the only thing in the water to eat The little boy, Alex, looked like a seal because of his lilo - similar accidents happen to surfers irl The two men on the peer were fishing - fish were easier to eat if hurt by hooks and this is likely when the shark took a real notice of humans, as it was dragging the peer away but turned around to chase the helpless Charlie swimming back to shore The man in the boat is the only other one I have trouble figuring out. This was after the peer incident so maybe the shark did because aware of humans and tried its luck
TL;DR: Hooper never hurt the shark, so it didn't bother killing him even when he was easy to kill. Quint injured it several times and it got revenge by eating him, Brody injured it and it attempted to get revenge but failed.