Life-long haunted human erstwhile pagan/student of the occult. So yes.

Most devastating: Meeting an actual demonically possessed individual. Took the best part of a decade to overcome the cognitive dissonance and for the penny to drop. Just over two years after last encounter the ptsd symptoms finally subsiding (the physical effects play out very much like the post viral syndrome after a novel corona virus infection ... you know, long covid?)

Man what a blessing! Lives were changed. Things got burned. Lessons were learnt. Jesus saves. The Rosary is a weapon.