Humans have fragile bodies and inflated views of their position in nature. All things in nature are in constant movement, and this is often diametrically opposed to what we want or need. I've heard a lot of outdoors-people say "mother nature is always trying to kill you". I disagree. Nature (weather, water, elements, whatever) doesn't care about you.

Wild animals view you either as a threat or (tasty) treat.

I'd rather not end up finding my way through an animal's digestive system.