The view is directly proportional to the potential for splatting the human body... the higher the splat potential*, the higher it looks... that's why the same distance over water looks far less than that same distance above pointy rocks.
* Often referred to as the pucker factor, due to the way it causes certain orifices to pucker up tighter...
the difference in how high it looks is perspective. Take the 3 meter diving board forexample. assuming you are 6'tall. standing under it looking up to the platform, you are only looking up four feet. standing on it looking down to the water looks like 16' .
adamtroyg, I agree on your perspective comments. The real issue isn't with falling, it's the sudden stop at the bottom that would bother me the most
Actually I've been up a few times. The more I do so the less concerned I am. Still not comfortable though.