I used to go caving in Texas and Mexico, in the late 80s and early 90s. Did some vertical work and a lot of crawling. I'm not very athletic, though, and no matter how hard I tried and how much I worked out, I still couldn't move through a cave like those who were naturals. Being somewhat afraid of heights didn't help.

I think my peak experience was rapelling into the Devil's Sinkhole in west Texas - scary as heck backing off of the narrow lip in a big hole in the limestone, but then being awed by the beauty of the bell-shaped pit with green plants growing along the sides. My favorite part of caving, though, was probably camping out on private ranches in Texas and in back country Mexico. I got to experience some truly wild and beautiful country that not many people get to see.
When I acquired other interests and quit caving every weekend, I gradually stopped finding out about trips and lost touch with the caver community. I kind of miss it, especially the back country camping, but I've got too much else going on and too many years have passed to try to get back into it. My ears still perk up when I hear others talking about caves, though, and I had to respond to this topic.