The psychiatric term for it is experiencing intrusive thoughts (or obsessive thinking,) but most of us know it simply as the inability to stop turning something over and over in your mind, to worry at it like a dog even as you desperately try and drive it from your consciousness.
I get it worst when I’m trying and failing to sleep. Sometimes, in those miserable minutes or hours, my chain of thought becomes so involuntary that it almost seems those thought processes have a serpentine life of their own, writhing and turning back in and over each other. Pulling up thought after awful thought until what is happening no longer feels like something I am doing, but something that is done to me.
I think this song (‘Serpents’ by Sharon van Etten) does a damn good job of conveying what it feels like to unwillingly torture yourself in this way; both in the case where her mind can’t stop running through the awful wrongs her partner has committed against her(first and second choruses), or whether its hopelessly looking for rationalizations which will enable her to forgive him for them (third).
Also her short-lived identification with the ‘serpents’ in the second verse is interesting; intrusive thoughts don’t always have to be taken as wholly external to oneself, there are ways of acknowledging them as somehow part of us which don’t overlook how unbearable they can often be.
But mostly I just think that the harmonies are stellar.