None of the examples shared so far were entirely out of the realm of possibility for my own thoughts, so I guess that’s a yes. I have come to think about this sort of thing as just the brain doing its job—generate hypotheticals to do dry-runs of scenarios, no matter how outlandish they sound.
I’ve sometimes heard that people are disconcerted by their thoughts when they find themselves considering actions they find abhorrent. But again, that’s just the brain doing its thing: it’s not you finding out that deep down, you’re really some horrible person having to keep their dark impulses in check, or else—your brain just does its job as general purpose scenario engineer, free of any value judgment, and then you reject those abhorrent to you.
So as long as these thoughts don’t become intrusive or obsessive, there’s nothing wrong with them. Whether they’re dark, or weird, or just not like you—whether you think about taking the baby’s candy, what it would feel like being the baby’s candy, or whether you’d like to dress up as a baby—doesn’t mean there’s anything wrong at all.
On the other hand, that’s a really deeply weird thought.
I once started to write a short story with that premise, but gravity only reversed for them. I stopped the project when I found myself spending entirely too much time trying to work out how to pee in sich a situation…
Not sure this counts, but…
I have read plenty of murder mysteries (fiction and true-life) and also quite a bit about police investigations, forensics etc, and so, sometimes (say, while out for a walk) I will think about ‘how to get away with murder’ purely as a mental problem.
Nothing personal involved at all. Just how I could fool the experts.
If Calvin ever explored that question, I don’t remember it. I think my proximate trigger was one of Heinlein’s books, where a seasoned spacer is described as “looking as though, if gravity were to suddenly reverse itself, he would land on his feet on the ceiling… which was of course true”.