Can't remember which one it was.
On top of that solid basis, you can introduce artificial inefficiencies, and then gradually remove them.
But you can't do the trick at all, if your rewrite doesn't start off being an orders-of-magnitude efficiency improvement.
Surprisingly, a lot of aerospace engineers are not super computer-literate. We used a clunky maneuver planning software for the geostationary sats that spit out our plans in an ASCII printout, which we then had to copy/paste out and manipulate using several consecutive shell scripts. I got annoyed doing it and so I rewrote the whole deal in Python, and just had it locate the file that had the printout.
When I first ran it, it had turned a 3-4 hour affair into about 10 minutes (depending on network connectivity). I showed it to my boss, and he was asking why it said "working...done" instantly. He said it looked like it wasn't doing anything.
So I added an aesthetic wait variable to the config and made it 1.25 seconds. So the user got to see "Working..." and then "done" would pop out, making it seem more like it was actually doing things to the layperson.
Last I heard they were still using that script for maneuver planning to this day.
But that's the techy point of view. Most non-techies will probably prefer feel over functionality. I think most people do. If something is instant, it feels too good to be true. If something takes ages, you'll get bored or frustrated. While things that take a proportional amount of time feel satisfying.
https://garden.bradwoods.io/notes/design/juice
"..." is a kind of juice
Scott: Certainly, sir. How else can I keep my reputation as a miracle worker?
Kirk: Your reputation is secure, Scotty.
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