The most astoundingly ill-informed conversation about sharks that I've ever been witness to, performed by a couple in their late twenties sitting directly in front of me on the ferry to the mainland:

Man: ...but if you were adrift at sea for a long time you would eventually just get eaten by sharks.

Woman: Honey, sharks don't eat people. That's a myth.

Man: Of course they do. What about that girl in Hawaii, the surfer?

Woman: That shark only took her arm. It didn't eat her.

Man: But it was going to. It would have if it could.

Woman: No, it wouldn't have. Human beings don't have enough protein in their bodies to satisfy sharks. That's why they always bite once and then let go.

Man: What do you mean people don't have enough protein? Of course we do!

Woman: (exasperated sigh) No, we don't. It's not enough to keep the shark alive. Sharks only eat certain animals that have enough, like sea turtles. The shark that attacked that girl in Hawaii was probably weak or sick, it's only the weak and sick ones that come close enough to shore to attack people anyway. It probably just took enough to survive.

Man: But don't sharks have to eat like a ton of food everyday just to survive?

Woman: No, that's another myth. They actually have to eat very little.

Man: Then why are there so many shark attacks on people?

Woman: Well, most of those attacks happen at night, when surfers are surfing at night, which you shouldn't do.

Man: Why not?

Woman: Because sharks sleep in the day and hunt at night. Sharks sleep on the bottom of the ocean in the daytime. But at night they come out, and in the darkness a surfer on a surfboard looks exactly like a giant sea turtle, which is a shark's favorite food.

Man: Yeah, I think I remember reading that somewhere.

Woman: So the shark bites once, realizes there isn't enough protein, and goes away. That's why most shark attack victims survive, the shark only takes a little.