Adding to my vote comment - I am a rock climber, mountaineer, expedition leader and former climbing instructor. That being said, I have a healthy fear of heights. That may seem strange at first, but it has what has kept me alive over a 25 year period of climbing. A climber who is not afraid of heights is a dangerous one and one I don't want to climb with. I have had a few climbing buddies who lacked this fear who are now quite dead from climbing accidents; I do not believe this to be a coincident. I still get knots in my stomach if I am up a thousand feet up on an ice face and look down. That is healthy.