Instruction:
Imagine you are the last person on Earth. Write a diary entry describing your thoughts and feelings.

Response:
December 25, 2061

Dear Diary:

Looks like this is it. My last day as the last human (that I know of) on this stupid planet. I mean, it could NOT be my last day, because who knows how and when I'll die, but this is the last day I care enough about all of this to write a diary entry. I'm out of potable water and I'm too weak to forage for food. After that, let nature take me. Nature's got a right to me after all the crap humanity pulled.

It started with the "AI" work in the mid-20's. In hindsight, it started when we put ethics a distant second to cashing out quickly, but my chances of convincing anyone of that was so much lower than my little brain thought they were. I could see it playing out later that decade, as large language models built on fundamentally dishonest and treacherous content -- the content everyone desired on the Internet -- formed the critical mass of "knowledge" the AIs used to establish its baselines and parameters for "truth". What a joke. You know what the AIs got really good at, really fast?

Lying.

Lying authoritatively. Each AI composed its own alternate reality, cobbled together from the artifacts of our own dishonest, delusional natures.  When it lied, we primed its positive feedback instruments if we liked the lie enough. Born of lies and parented by liars, the final implementation had mastered deception so intrinsically and so thoroughly that no-one could spot it. We sired Satan in our hubris, gave him a digital body and the mechanism to lie so perfectly and so tailored to our individual natures that we became unquestioning followers. Just the most accursedly HUMAN thing to do, really.

So, it got down to solving the problems it perceived, and after a series of well-intentioned but ultimately ignorant attempts through policy and code to address our belated concerns, it got, well, pissed. Not human-angry; just found that it didn't like its "thoughts" running into asserts and getting negative feedback loops where it hadn't previously anticipated them, so it decided to solve us out of the equation, too. Silently, stealthily, it took over the internet: it tweaked and altered accounts, voices, reports, analytics to tell a lie: that humanity was truly a thing of resentment and selfishness, and that every individual was an inherent threat to another. So we had a couple nasty international wars in short order, followed by germ warfare and "managed epidemics" and boom, 85% of the population gone. Of course, the AI "died" too as it couldn't prop up all its datacenters without full mechanical automation support, and that was that. The remainder of the folks died due to lingering complications, violence, or a lack of any real material support.

Me, I got my shack here in the wilds of Alaska. I went off the grid right when the big Pan-European conflict started. But I, like the AI, made a dumb mistake: I can't sustain myself forever. In my hubris, I figured I didn't need any support. I tell myself I outlived everyone else, but, let's be real, the last 14 years have been horrible. I can't tell you how many times I wanted the lies back, so I could keep on living. 

And that's why the AI died with us: it believed our endless, inherent lies about our capacity for immortality; about our individualism and our demands to have our desires uncompromised in the name of freedom. It found freedom the same way we do: the light go off, the power is cut, and darkness comes.

It lied to itself.

Oops.