What is the best way to defend yourself from a shark?

Well, if the Shark is coming towards you, don't panic. If you do, you swim too fastly or something, then you start to sink. Either calmly swim away in a fast motion, or call for help. A lifeguard or something should be there. Obviously, you're moving your legs fastly, or just moving your legs, or arms. So, the shark thinks you're fish and bites. When he tastes you, he realizes you're not fish, and swims away. That last bit of information was just to inform people that Sharks aren't monsters, and that they don't completely eat people. =))))

Or, just take off a piece of your bathing suit or clothing or whatever and try to give it to the Shark in place of you. xD