My fantasies are a bit more charitable: Taking long dead people for a tour of the present, to see the consequences of their discoveries.

As a kid I used it as a way of analyzing the ramification of singular ideas, or understanding the complex phenomenons that interplay in technology. Eg, I would break down how a computer works (from the plug to the screen) to Benjamin Franklin, who would appreciate why you'd want to arrange silicon to make the thinking for you.

In adulthood they've quietly settled into the occasional "Man, I wish Kepler could play Kerbal Space Program".

That's really funny. I love the weird fantasies we cook up.

I have a variation of this, where I travel back in time to before some long dead person did what made them famous and tell them all about their discoveries and all the wonders that came from it.

It's usually accompanied with a hint that they won't remember our conversation, so it won't affect history, but they'll enjoy marveling at it for a short while.

I usually have a fantasy where i travel back in time to middle ages/ancient times and try to:

* convince people i am not a devil worshipper/magician/time traveler

* explain how some concept works.

Imagine trying to explain electricity to Pope from 1000 AD, or mathematical functions, and integration/derivative to Greek philosophers etc.

I do the same, but for things that aren't yet discovered. I try to imagine what the solution might look like, how it would be presented, what the implications of it's creation will be, etc.

I really love for example the film 'Travelling Salesman' [1]. It explores some possible narrative for discovering the solution to P=NP.

One I like to think about is general human-like AI. How do I test it works correctly? How long did it take to create? What algorithms does it make use of? What are the implications in my social circles? What is the wider impact? What happens if you refuse to release the code?

One film I like that explores some ideas is 'Ex Machina' [2]. In my opinion the AI created in the film is intelligent, but lacks empathy - something I think we should seriously consider in our attempts to create AI.

[1] https://en.wikipedia.org/wiki/Travelling_Salesman_(2012_film...

[2] https://en.wikipedia.org/wiki/Ex_Machina_(film)

I was daydreaming a lot as a kid about all sorts of fantastic stuff. At some point I stopped.

I wonder what else was gone with that daydreaming, because it feels like a thing you want to be doing, something that works your imagination.

I often imagine long lost realities with a twist. E.g. what if the Mayans had electricity? What would the lamps look like?

I do the same thing all the time!

Oh thank god. Daydreaming Temporal Plagiarists unite!

Probably worth noting in this context, I recently started reading a book called "How to Invent Everything: A Survival Guide for the Stranded Time Traveler" which, basically, says: "If you happen to be in this timeframe, invent this trivial thing. It was invented that many years later by this person, but of course you can keep all the fame to yourself".

I lack the imagination to go back with anything more than some information that will make me rich, lottery numbers usually and only back to the previous saturday.

Not exactly, but I do often find myself trying to imagine how I would react to being the person who discovered that thing.