When I was a kid, I thought this would be the best job. Cleaning the insides of the giant tanks at an aquarium, and holding yourself in place with a little suction-cup handle. I'm not sure what about it appealed to me so much...
For a while there, I wanted to be a marine biologist. Maybe it had something to do with that, although cleaning tanks is only obliquely related to marine biology. Maybe it was the free-floating aspect of it - the little suction-cup handle made it clear that without it, you'd have no leverage for cleaning the window and you'd float away. Maybe it was the appeal of being inside a photograph - the exotic colored fish in the impossibly green water wasn't real on this side of the glass, it was more like watching a movie. But on the other side of the glass, you were really there.
I can tell you now what doesn't appeal to me about that job. I don't really like the idea of not being completely surrounded by breathable air (which is why I'll never be an astronaut). I don't really like to have lots of people looking at me; performance gives me hives. I know I wouldn't be putting on a show or anything, but I also know that as an aquarium visitor, I'm much more interested in the window-washer than the fish. I don't really like to swim, nor do I like wearing the things you need to wear in order to swim - they're uncomfortable to wear, uncomfortable to put on, even more uncomfortable to take off when they're wet, and then putting on dry clothes afterward is uncomfortable, too.
Oh, and fish are creepy.
Good think I never became a marine biologist, eh?