https://chroniclevitae.com/news/814-is- ... _medium=en
It is worth noting here that there is a difference between mean and completely clueless. Some people are not mean spirited; they simply lack awareness about their impact on others. Rehabilitation is far more possible in those cases.
As I’ve reflected on who might be worth saving and on my own missteps in trying to chart the right path when faced with difficult people, I have concluded that it is best to invest resources in those who are curious about how they are perceived -- and not in those who want to prove that what everyone else is saying about them is incorrect.
Here's a quick test: When you express concern about someone’s bad behavior on the job, is that employee’s response characterized by regret and curiosity ("I can't believe I have had this effect; is there a way I can turn this around?") or by anger and defensiveness ("Exactly how many people have complained about me? What were their exact words?"). If it's the former, do your best to offer assistance. If it's the latter, start planning for the employee’s exit.