I don't condone revenge, but I don't see selfishness in the desire to retaliate. A man's mother was killed, and he knows exactly who did it. The man loved his mother more than anyone, and besides, this woman was a doctor, not just any doctor – a surgeon, and every day she saved people's lives. The man is consumed by rage, hatred for the killer who not only deprived him of his mother but also many other people who needed the help of a wonderful doctor. After such a vile act, this killer has no right to exist; he MUST die! He must die for the deaths that occur in hospitals because of him! After all, in the whole city, only his mother was capable of performing heart surgeries! Why did he do it? WHY!? Killer!!! I hate him!!! I will find him!!! I will make him pay tenfold for my mother's blood!!!

That's how a vengeful person is born. If we speak in general...