I really want to know why we keep ourselves alive.
Man's most powerful instinct--the will to live! Life is the only thing we've ever known. We don't know what's beyond it, only that the living are simply "left behind", and that seems to be the greatest evidence for there being something after life. But, it seems to us to be an unearthly place, somewhere beyond the stars where no human being can reach while being alive; the afterlife is the only true unknown (or "the one new thing under the sun", which is ironically not under the sun at all).
To support the afterlife comment--when someone dies, what is said about their material possessions? That they were "left behind". But you can't leave something behind without going somewhere; car keys can't be considered "left behind" until the owner has actually left the house. So when someone dies, how can they "leave behind" their belongings unless they've actually gone somewhere else?
Where do they go? I dunno. Being a living human, I'm the least qualified to answer that question.
As for "humans being more complicated than animals", I think that desire to prove that is the basis of civilization. Animals do what they need to do--eat, sleep, fuck. They sometimes travel in packs, because there is safety in numbers, and they seek out environments most conducive to their comfort and well-being.
They don't build cities and churches and governments. The most they'll do is designate an "Alpha Male" because--let's face it, the strongest creature should be at the top of the pyramid. They abstain from building monuments to their "complexity" because they have nothing to prove. They realize that the moment a building is erected signifies the first step in that building falling down.
Ironically, animals are the most Satanic of us all. Animals don't have churches--and Satanism doesn't either.
The difference? Opposable thumbs. We're the only creature to have them, and we feel the need to "prove" that they are there for a reason. So to prove our superior intellect, we build skyscrapers and airplanes; we write books about Gods and then kill each other about them; we invent guns and bombs and then use them to destabilize an already fragile race of beings.
So why do I live?
I believe that asking that question is the first step toward questioning oneself. Questioning oneself leads to doubt; doubt leads to fear. And fear leads to the need for comfort, the need to know that we are better than something/someone else--or just the need to know we're more "complicated".