A number of narratives have thought about what the world would be like for the last human alive, ranging from the bleak life of a man with broken glasses who just found the time to read all he wanted in The Twilight Zone, to more comedic approaches like the first episode of Last Man on Earth (the only episode I watched). Aside from portrayals which attempt to say something about the humans who are still alive together, how would a final Human live?
The nature of the essentials food/water/shelter would depend of the type of Apocalypse, so we neglect the “how” of those and suppose that our person has bountiful access to the essentials. What would this person do for fun? How would they spend their time? Obviously it would depend on the person, so let’s ask a slightly different question: What is there that this person could do?
For starters, they could walk or bike on any stretch of road they please. I have an aesthetic fascination with walking in the middle of the empty street, and have always wondered what it would be like to bike down the long, winding stretches of highway between cities.
This person would be able to see all the stars in the sky, because there would be no people creating light pollution. If this were a particularly science and tech savvy person, they could get a lot of good astrophysical research done.
Given enough time, they could travel the world by whatever transportation method they liked. I admit I know nothing about flying a plane, but I would imagine that one could read enough books and rely on modern convenience enough to figure out how to fly a plane. Same with other transport.
They could leave a mark for aliens, or time travelers, or interdimensional travelers provided any of those groups exist, and they felt it was worth their time hedging that bet.
They could see every sunrise and sunset they wanted, and all the other wonders of nature that might still be around, or have grown back over time.
They could be themself. With no other people around, this person could wear what they want, and exist how they feel, without the pressure of performance that is wrought by the gaze of another.
This person could do a whole lot, and a whole lot more I’m not even aware of.
All in all, this person could live, despite the lonely and bleak future. Some might say they could live in a way nobody else had previously. What else could they lose in the process? Nothing and everything.