Setarkus

Sometimes during a car ride when I'm in the passenger seat, tired, and there's no conversation going on, I close my eyes and let my thoughts wander.
I also tend to focus on sounds, things I feel and also whether I can recognize where we are approximately by the car's movement and the lighting through my closed eyes. It's kind of a habit I've taken with me from experimenting with some meditation that I still do when just relaxing for a bit.

Occasionally, I drift off to imaging some stuff, like continuing a conversation or a scene of a story I just thought about, taking a walk somewhere or other simple things like that.
I'm still aware of everything else around me, just that my focus is more on my imagination process. Usually I also ponder when to open my eyes again to check whether my location estimation is correct.

Just recently, I was imagining a conversation between two people, one advising the other on some matter they had a discussion about. I kinda slipped more into the role of the "teacher", while still also thinking about how the "student" would react.
The scene was sort of visible, yet not like a true dream.
At the same time, I noticed a shadow passing over us (the car), and thought to myself "oh, so we just passed the bridge", while continuing the internal conversation.
A bit later, after some turns, I wanted to confirm if my guess about our location was correct and opened my eyes in the middle of the conversation.

My guess was correct, and I tried to remember what I just thought of, as it seemed like I was at the verge of falling asleep. All details I just had in my mind a moment before were gone. All I could remember was that one person explained something to another, and that just barely.
Any content of the conversation I just held has vanished, no idea about the topic, what relationship the people had, how old they were or what they looked like.

That's the usual thing that happens, though I rarely remember anything at all other than it was kinda fun and that I'd like to continue, but can't.

A "deeper" kind of daydreaming

So, I've been writing down my dreams for quite a while.
I usually write short notes on a piece of paper right after waking up (provided I remember the dream well enough) and then write it in a book some later time so I can focus more on getting all the descriptive details in.
For each dream I also write down a title at the beginning so I have a sort of table of contents. I'm mostly able to remember what dream it is by looking at the title as it's something that stood out in that dream or because it's the general theme of the dream.
A few days ago, I wanted to look up one of my dreams to confirm something. I found it right away as the first entry, confirmed what I wanted to and then looked through the other titles for nostalgia's sake.
That's when I noticed one title simply saying "Nightmare" on page 111. Nothing else. I was kinda amused, wondering what kind of nightmare it had been for me to only write down this one word. I was like "Oh let's take a look at that, I wonder what kind of horror that was. Some emotional terror? Some jumpscares?"
When I got to the entry, I only read the first sentence and immediately recalled the whole dream. My first reaction was to look away from the booklet, closing it and exclaiming "Oh fuck no. Why...". It wasn't any emotionally painful dream or jumpscares but rather the kind of silent dread that something is very much not right and that I'm in grave danger, then people acting weird and getting threatening.
I was kinda amused after accidentally remembering it, though I was actually somewhat frightened then, or at least more alert, like after watching a horror movie.
It didn't help that I did that just before going to bed and I was kinda laughing at and cursing myself for naively checking the entry simply titled "Nightmare", probably to avoid myself casually remembering it.
Or maybe I was like "Hey I bet I can make myself remember this some time because I'll be too curious to find out what this obscure title means."