However that all changed with I heard and felt a deep resonance with the budding HFY community on the internet. This clarified the central theme of my universe. Humans are Weird. Very, very, weird.
However, while the author side of me was very happy with this idea, the wildlife ecologist side of me wasn't quite satisfied with it. You see there is a basic tenet in biology, form follows function. All those science fiction universes that set humans as the boring, normal baseline species did so with an actual practical reason at their backs. They assumed that Earth was a boring normal planet. "Class M" in the Star Trek universe I believe. M for mundane.
If human were going to have the form of 'weird' in my universe there had to be a function for it. That function was obviously survival on Earth. So if humans were going to be significantly weirder, significantly tougher, significantly more dangerous than other species than Earth had to be a seriously messed up place.
So in my universe I set Earth as the absolute extreme environment that could sustain intelligent life. Earth is a death world full of volcanoes and storms that will rip mountains down, and plagues of locusts that would devour every green thing.
In crafting the other species in this universe I began to ask questions like what would a species look like that had never once had to flee a predator? What would a species look like that couldn't conceive of the concept of a natural scarcity of resources? What would a species behave like that had never once experienced a viral pandemic? But most importantly, how would all of these soft creatures respond to humanity?
The best summation of this concept can be found in a Tumblr post doing the rounds. This is that post.