The difference for me is that I would assume the glass box wouldn't fall apart. But grates rattle, etc., so I'm always sure when I step on one that it's going to open or break or something.
A zipline I could do as long as someone gave me a push, I think.
I've done #2 on this list:
[link]
I did an upsidedown zipline once. That was some freaky awesome shit.
A zipline commuter service would be perfect for North Beach. Or meara's neighborhood in Seattle.
I seriously was afraid of both the monkey bars and the slide as a child. There is no way I can do any of this.
I would join in this conversation but I have to go climb a ladder.
I've still never been able to do a somersault.
We totally used a zipline as transportation during the summer we were at the big camp. We had to con campers into carrying our gear back to the start for us, but hey! It was way faster than walking and we'd been ziplining all summer.
I love heights, but I get the fear of falling off something high, coupled with a suspicion that the monkey brain is shrieking "Go for it! Jump! It'll be awesome while it lasts!" I have freaked out people I've been with re: heights.
Hubby didn't have a fear of heights till he suffered inner ear damage in a firefighter chopper crash. I've seen studies that a lot of the space-related phobias are related to such damage.
I have much more fear of mechanical failure than fear of heights. But also a large streak of fatalism, so maybe I could manage to force myself onto one of those clear thingies.
Although I actually have a stronger reaction to other people being near edges of cliffs and whatnot, so if there was a crowd that would probably be bad for me.