Maybe it's because I never saw Jaws?
Almost assuredly. Especially the opening scene scared the you-know-what out of me. For me, it ranks right up there as one of the scariest movies I've seen. Scary movies are most scary the first time you see them. The opening scene always gets me, though.
Edit: I was happy to see that the great white was recently discovered to have another sea swimmer to fear. A show recently said scientists have discoverd that killer whales attack great whites as prey. When a killer whle killed a great white near the Farallones, all of the great whites immediately left the area and did not come back that season!
They got the first ever video of suh an attack. The killer whae snuck up and rammed the great white, turning him and holding him upside down for about 10 minutes. Being held upside down paralyzes the shark and the killer whale can drown him that way.
I also didn't know that killer whales are the largest member of the dolphin family.