I did retirement home training and used to think it was a sweet job. Then I got in the business and underestimated how demoralizing it was as they give you the easy elders in training while the others make you, or at least me, really think of the fact the job just amounts to an unkarmic freebie.
Some of them certainly did. My younger brother, for instance. He's quite literally a psychopath. There's no cure for him, no rehabilitation that would fix him. The best that can be done is keeping him out of society for as long as possible. He was in and out of juvie starting at about 11.