I've spent the last year being a travelling cultivator, so helping people with hauntings. And resentful spirits, demons and so on. Where I come from there's enough of a need for people to be skilled in the art of making dead things move on. Or at least stay dead. Mostly. Sometimes the dead are useful
Resentful energy's bad for you, though. I would suggest trying to cleanse yourself of it as soon as you can so it doesn't harm your body.