I grew up in Oz. When I was 15, I took the family boat out and dove the reef myself to clear my head (mistake #1). I was down at a depth of about 28 metres (90 feet) when I was only rated for 60 feet (mistake #2).
Whilst diving, I spotted a 3.5m Mako shark coming right at me. For those who are unaware, Makos are basically the cheetahs of the ocean, and they only have two speeds: Curious (harmless) and lunch (very much harmful).
This guy was in lunch mode.
So I hovered, as I had been trained to do, as there would be no way for me to outmaneouvre it or escape it. Nowadays, we dive with Shark Shields, which emit electronic pulses that freak the sharks out and keep them away, but back then, what we used was essentially a chainmail sleeve. The idea being that sharks hate the taste of metal, so if you give it your arm, it'll bite down, decide you're gross, and move along. So I wait, and it comes, and I do a perfect move to give the beastie my arm. Just before the cronch, however, it occurred to me that I had left my sleeve on my bed (mistake #3).
I had my kelp knife drawn, and stabbed it right as it bit me. It swam off, and I was alive, however, now I had a series of problems:
I had HUGE open gashing wounds on my arm from the bite in open water, and was trailing blood everywhere.
Once the shock wore off, you realise that you're in salt water, and salt and open wounds don't feel good.
In a panic, I dropped my weight belt and shot up to the surface without any sort of waiting period (hello bends - mistake #4).
Because I hadn't been paying attention to the currents, I was approximately a quarter mile downstream of my boat, which means I had to swim up to it (mistake #5).
When I got to the boat, I really started to wish I had done as my Da had said and had the comms fixed (mistake #6) or that I had upgraded the first aid kit like I had been threatening to do (#7).
So I end up racing back to shore with nothing more than a toruniquet to staunch the bleeding.
Long story short, my series of unfortunate self-inflicted events earned me 172 stitches, boatloads of physical therapy because the shark had actually bitten down on my tricep and detached it, and easily identifiable scars on one of my arms for the rest of my life.
Make sure to keep an eye out where you delve, where you explore- for if you dont, you never know what might be curious or what might be looking for lunch. Run and hide. Duck and weave. Explore and stay close with your friends.