I picked up Charles Yu’s How to Live Safely in a Science Fictional Universe yesterday and I’ve just been plowing through it. A passage from early on in the book:

The earliest memory I have of my own dad is the two of us, sitting on my bed as he reads me a book we have checked out from the local library. I am three. I don’t remember what the story is, or even the title of the book. I don’t remember what he’s wearing, or if my room’s messy. What I do remember is the way I fit between his right arm and his body, and the way his neck and the underside of his chin look in the soft yellow light of my lamp, which has a cloth lampshade, light blue, covered by an alternating pattern of robots and spaceships.

This is what I remember: (i) the little pocket of space he creates for me, (ii) how it is enough, (iii) the sound of his voice, (iv) the way those spaceships look, shot through from behind with light, so that every stitch in the fabric of the surface is a hole and a source, a point and an absence, a coordinate in the ship’s celestial navigation, (v) how the bed feels like a little spaceship itself.

People rent time machines.
They think they can change the past.
Then they get there and find out causality doesn’t work the way they thought it did. They get stuck, stuck in places they didn’t mean to go, in places they did mean to go, in places they shouldn’t have tried to go. They get into trouble. Logical, metaphysical, etc.
That’s where I come in. I go and get them out.
I tell people: I have a job, and I have job security.
I have a job because I know how to fix the cooling module on the quantum decoherence engine of the TM-31. That’s the reason I have a job.
But the reason I have job security is that people have no idea how to make themselves happy. Even with a time machine. I have job security because what the customer wants, when you get right down to it, is to relive his worst moment, over and over and over again. Willing to pay a lot of money to do it, too.