It starts with some free time,
Nothing to do, no desire for anything, nobody to talk to or just no will to
Just lay down for a while, wait for something to happen
No matter how hard you try your mind will inevitably start to drift off
Somewhere more interesting
Down memory lane
It stops at random each time
And starts analysing it, from beginning to end, taking each little sliver of a second apart, finding the silliest "mistakes" you've made and fixating on them.
Bored turns to stressed, stressed turns to dreadful.
And dreadful stays