I love swimming. Like, really, honestly love it. I like sculling underwater, and feeling like a fish, or a mermaid, and knowing that my legs look good in a swimming costume.
But, (isn't there always a but?) I only like swimming in a pool, or in the sea where there's sand. Because I'm really, really scared of stuff underwater.
I can just about stomach going over medium sized patches of sea weed, and some smaller rocks, but big rocks, chains, boats, holes, big bits of sea weed.... they freak me the fuck out. I've always assumed it's because you never know what might be hiding there. Imagine swimming over a rock and then seeing a a skeleton with an octopus nesting in the rib cage? I mean, not that that wouldn't be totally awesome, but you know what I mean. I do not want anything with more than three legs stuck inside my chest cavity.
The worst is definitely chains though. I.e - what are they connected to, whats stuck in them, are they going to shoot out and grab me? Sort of thing.
I used to always dream about going down and exploring old shipwrecks, and finding strange, long forgotten objects left by some long forgotten people. But even in my imagination, whenever I got close to the wreck I'd just end up flipping out. Open a door? Sure thing, but there ain't no way I'm going through it.
Underwater pirate zombies are a never ending problem.