I ended up just making up a fake story on the spot that was uninteresting and barely coherent. That was the first question I was asked in the interview, and made me nervous for the rest of it. Didn’t get the job.
Clearly I should have taken an improv class in preparation.
But yeah, I learned the same lesson as you: prepare and rehearse a bunch of fake stories in advance. Completely stupid waste of time, but necessary.
It could be an interesting part of the interview that reveals a lot about the candidate, but realistically it’s going to favor the people with rehearsed fake stories. What are the chances that your genuine real-life experience is more interesting than someone else’s fake one specifically crafted to be as interesting as possible?