As a person who does enjoy being in
nature, you can discount this opinion as
conjecture. Then again, what is an
opinion, anyway?
The human race has done a lot to separate themselves from nature, both physically and mentally. When confronted with nature, in all its stinking and intimidating glory, some people may feel threatened, or pressured to prove their distinction from nature.
This brings up two interesting points.
The society that we build up around us, in the beginning and now, can be seen as a wall we place between nature and ourselves. We, as a species, are weak. Our skin is thin, and we have no natural weapons (like a bear's teeth, or a cat's claws). Without this protective wall of buildings and such, we would fall prey to weather as well as other animals.
Secondly, and I think, more importantly: can we, humans, a natural animal in this world, do anything that is unnatural? In the words of Love and Rockets, "You cannot go against nature, because when you go against nature, that's a part of nature too." While trying to avoid a debate on the validity of the theory of evolution, nature IS an evolving thing. The way that bears evolved to have large jaws, we evolved to have large brains, giving us the ability to build society to protect us form the physical dangers of the (what we now call) natural world (which we never stopped being a part of).