I had an exit interview once.
I worked in a school and the exit interview was with the line manager that was such an incompetent, nasty bitch that I handed in my notice after 6 months.
I was very honest with her and told her I was leaving because of her and her inability to do her job correctly. That she had made me miserable, constantly changing my job description and duties and making me do things I couldn’t do without infringing on my actual job and then reprimanding me for it.
She tried to change the good reference she had given me a few days previously for my new job. Totally retraced it and gave a really vile, rubbish one making me out to be the devil.
Luckily, I was going back to the job I had left for the school (care work, they are always desperate for anyone so bit my hand off when I wanted my old job back 😂), my old boss called me and said, “wow, so what happened? They suddenly hate you!” She found it hilarious that she had thrown such a strop.
(I was totally justified - this school business manager started at the same time as me, since I left that job, no one has stayed in it longer than two terms.)