Well I tried to explain to him that if he pulls the group and then I sleep one of them that it's not necessary to try and regain aggro on the slept monster. But he kept raging that me sleeping them reset the aggro and that I was taking hate of those monsters. The main reason I was sleeping was the summoner was not very good and things were taking very long to die and I wanted to make my life easier as the healer. I'm a very competent healer and use medica very rarely as to not steal hate. So it pissed me off that he said I need to learn my role. I don't tell people how to play and talk down to them at the same time. So I don't expect others to do that to me. I wasn't even mad at the fact he kept attacking the sleepers, he could have said hey no need to sleep I can handle it or something like that but he went straight to cussing and insults.