Seems that much of life involves control of negative emotions, while at the same time having the judgement to know when and how to resist darkness.
Focused negatives towards another turning to focused negatives towards a group, and then to larger groups.
Where one reacts to barbaric acts with similar barbarism, or with unfounded generalizations as to the nature and extent of barbarians.
In The Grid (2004), Emily Tuthill, played by Jemma Redgrave, decides to resign from M16. This after shooting the mastermind behind a number of terrorist attacks, who was her prisoner, but who triggered dark emotions in her, through cutting insults.
She forced him out of the car and shot him.
She decided to resign because she found that she was becoming like him.