I guess it depends on how it is done, when I was a student nurse a couple of friends decided they were going to get me over my fear of heights so arranged an activity weekend with me. It started off well enough, rock climbing and a bit of abseiling was fine as long as I didn't look down so they decided to take things a little further......bridge swinging and a bungee jump (the latter they didn't tell me anything about). If you haven't heard of bridge swinging its basically a massive rope swing under a tall bridge or viaduct, jump off and physics does the rest.
Then came the bungee jump, I wasn't overly happy when they sprung it on me but I decided to give it a go anyway. What I hadn't been told was that there were to kinds of jump available, normal and 'daredevil' where you end up dropping far enough that your heard ends breaks the surface of the river below.....
No prizes for guessing which one that pair of evil feckers signed me up for.
On the plus side I have to admit while I'm still not keen, I'm not as bothered about heights as I was before, but falling on the other hand...