I've heard that lions and tigers aren't actually that dangerous. Some big cats have a very vicious fear response, but lions and tigers are apex predators, and no one in their natural environment can really fuck with them, so they've lost that kind of behavior. The only real risk with lions and tigers is if they get hungry, or if you try and play with them, because they don't really realize how strong they are.
I'm not going to test this theory myself, but here's a cute story about a lion who was raised by humans and still recognized them even after being reintroduced into the wild: http://en.wikipedia.org/wiki/Christian_the_lion
I think that to respect Nature you need to understand that it won't kill you 'just because' you get out of your safe house. Nature gives you a lot to take care of yourself. You need to learn to properly understand it's signs, that's where you can start respecting. Otherwise you have fear, but not respect. You can't imagine yourself sleeping under a rain, can't you?
I am having a hard time trying to verbalize the difference between knowing something is there and experiencing it first hand and the difference. I think there is a difference, hopefully someone more eloquent than myself can explain.
So the people who don't risk their lives climbing mountains have lost their respect for nature? I think you might have that exactly backwards :)