OMG, it’s incredibly, profoundly difficult to talk about this.
Here you have such a verbally unmatched phenomenon with so much of that weird colliding context and fluctuation in generic communicability that you might as well explain to a 2D entity how the third dimension works.
It is a miracle I even was able to recognize it by name when I first came across it.
In ancient times, it was said that the Persians would debate their ideas once sober and once under the influence in order to align clarity with perspective, and here you have this thing, which sees this and is like “hold my beer”, fading in and out like old age, flickering the old internal lights without anyone’s planned consent, and misguiding thought navigation.
I cannot speak for everyone, but there are a number of us who will tell you they don’t dare write fiction (or nonfiction?) if there isn’t absolutely every reason to believe they’re in the safe zone, mind’s eye, verbal recall, and comprehension (including that of relevance, which already has a relative nature) be damned, further complicated by the “there are different kinds” which ranks it in the realm of “phases”, “moodiness”, and “DID alters” (my step-step-kids each can attest experience with one of those three).
What does your own mind match it up with?
Brain fog feels like there’s an invisible film over your mind that slows down your processing, like there’s a latency to all of your thoughts. It sort of separates you from how you’re experiencing the world and makes everything less clear. Sort of like the mental version of trudging through a muddy swamp. You’re less alert.
Usually it’s also coupled with just feeling generally tired and out of it.