In reply to brt: For me, definitely the latter. I couldn't see the attraction before, and I still couldn't see it after. The programme reinforced my view that caving seems to consist of going through dark, dirty, claustrophobic places in order to arrive somewhere equally dark and dirty but, if you're lucky, slightly less claustrophobic.
I couldn't get my head around how some of those squeezes and sumps were first explored. How could anyone set off in to a narrow space where it becomes impossible to reverse your route, when you don't even know whether it leads anywhere? At least with a mountain or a crag you know that there's an end point to aim at ie the top.