I'm not sure what it says about human nature, but I can't help noticing how people can be so much more civil to each other when they meet on these trails. We smile to strangers and even say hello as we cross paths, when we do it up there in the woods. Were we to meet the same strangers on a city street, however, these sincere smiles would probably be grounds for suspicion.
The farther we get from civilization, the more civilized we seem to become. (As long as there's a clear way back to civilization..!)