I don't know about you, but with me it wasn't even so much about certain situations. It was more that my mind just needed to have something, anything to obsess about. I had many sleepless nights over things that, looking back on them now, weren't really all that big a deal.
If it wasn't one thing, then my mind would latch onto something else. With me it was mostly work or partner issues, but if nothing was going on there, then I'd find something else, like my health or my in-laws or the neighbours. I seem to have come out of that, but now when I remember being that way, it was like I was living in a certain type of hell.
For me it wouldn't even be so much what a person is even doing, but simply more of a need for my mind to obsess and that itself is what needed to be addressed. It sure wasn't easy to get out of that in my case and took a long time; I did a lot of reading and searching for answers and practicing the art of acceptance and letting go. But what an incredible relief it is to have managed to escape that crazy-making prison that was my own mind.