Why do I suddenly remember every embarrassing thing I’ve ever done right when I’m trying to fall asleep?

I’ll be perfectly fine all day, but the second my head hits the pillow, my brain decides it’s the perfect time to replay that one awkward thing I said in 7th grade or that time I waved back at someone who wasn't waving at me. Is there a biological or psychological reason why our brains "attack" us with cringe memories specifically at night?