I can not stop saying words or phrases backwards in my head. Started when I was about 6 and an adult told me what my name was backwards, and they mispronounced it. I corrected them and haven’t stopped since. I even have my own rules of pronunciation for certain letter combinations in reverse.
Similarly, I obsessively make my own version of spoonerisms where rather than two elements of words being swapped, all similar elements must be transposed. ie, All Os must be swapped with all Es in a word or sentence.
An example – the sign for Leek New Road reads Look Now Read in my head. (That’s one of my all time favourites and caused me to shout out loud in excitement in the car when I discovered it 😳 )
I have a notebook for the more pleasing ones…. 😳