>>319768they happen every time people go to sleep.
it's just that the way we all learned to fall asleep as kids is by tuning out from them so most people never notice them as adults, just like when someone is talking to you and you're distracted so it's as if you hadn't heard anything.
and we're all so distracted in our heads all the time anyway, so it makes sense that it's rarely talked about even when it's inherently common and natural to everyone.
yours are probably nightmarish because of anxiety or obsessive thoughts, which itself is probably why you seem to notice them more than most people. anxiety and obsessive thoughts can also make people, for example, get stuck on manual breathing for days or weeks at a time, which is hell, until the anxiety decides to move on to some other random thing to torture you with. but that's just my experience with it, so it's probably a very limited perspective.
>>319777i also hear voices, but i haven't yet noticed them say anything of significance.
>>319779in my case i sometimes see flies flying around. maybe because i don't mind spiders but i do flies.