First off, the movie Orca sucked. It was horrible in story and special effects. A killer whale is not to be messed with, but if those people ride it at Sea World for the price of a few tuna, then it is nothing to the Great White Shark.
Sharks are fascinating, but to be watched from a distance.
Did I share my shark encounter story from the Marshall Islands? We were swimming near a place called Bieje Island. Shallow water, about 30 feet, only 50 yards from shore. My buddy called over and said it was coming my way. I looked down, and it was already there. It did one circle and left. Now, I have never seen any other fish swim towards you, ever. I was told after he did the circle because he was sizing me up for a sandwich, and decided to pass. He wasn't even that big, only 5 or 6 feet long, a white tip. But it absolutely scared the shit out of me. I realized as soon as it left in that 3 second encounter, there was not a damn thing you can do in the water.