Did you see the spectacular photos from 2003 where a surfer is accompanied by a big dolphin looking like a shark? Well, it just looks like a shark but apparently is a dolphin (you can tell by the top fin). Well, here's a photo of a guy in a kayak being followed by a great white shark.
Accordning to Snopes.com the photo is real and fortunately it's a safe setting. The guy in the kayak is a great white shark researcher. Even if it is safe, they didn't know that until after the experiment :)