Death by free-fall. Not heights, not death in general, but death by free-fall. I have no idea why but the thought of falling from a fatal height makes me feel horrible. It could be that I have an easier time relating to falling than other kinds of death, as I've "fallen" from high places before (cliff jumping, bungee jumping, etc.) but have never really had an experience with any other deadly acts. It seems irrational to me, as there isn't too much else that truly scares me (not talking startling) that I can think of, and I've never been able to come up with any potential causes.