In the few cases where surfers are attacked it often proves fatal and those lucky enough to survive are left with terrible scars. Back in 2007 there was an amazing case when surfer Todd Endris was grabbed in the jaws of a shark. He was sitting on his board oblivious when the shark hit him and it managed to get both the board and his torso into its huge jaws. The skin was ripped from his back and his leg was cut through to the bone. He kicked the shark in the nose until it let go and much to his amazement a pod of dolphins happened along and circled him, protecting him as he rode his board into the beach and safety. Apparently there have been other cases of dolphins protecting victims of shark attack but you wouldn’t want to rely on it.
Just to show sharks aren’t always a threat to surfers here’s a video of a guy catching a lift from a shark. I wouldn’t recommend you try this.