First one would be getting tosses on a think wave having the board nose dive and me fly off backwards... Only to come up and find that my leash dug into the back of my board (One of my favorite fish style boards). Had a good 6inch gouge from the leash on that one...
Another would be when i got stung by a string ray coming in from a session... WORST FEELING EVER!
The last would be running from the cops for doing stupid things back in high school.
Went swimming in a hot spring that drained into the ocean. Sounds great, right? Well, it's not when you realize you're swimming with hundreds of eels and sea snakes.