I'm not afraid of heights........... I'm afraid of falling from 25 feet with nothing between me and planet Earth [:-].
The only time I get nervous is when the wind starts blowing hard. I had a tree blow down about 40 feet away from me one year. It was a pretty scary experience.
Actually that's about the only time I get a little nervous. I've seen the same thing happen and it makes you wonder after that. Whenever the wind starts blowing good I start wondering how sturdy the tree I'm in and the ones around me are