Person A harms Person B unintentionally. Person B retaliates and harms Person A intentionally. Person B believes herself to be morally superior. Person A either believes the retaliation to be justified, or retaliates and harms Person B again, this time intentionally. Repeat.

The tragedy of humanity.

. . .

Person A harms Person B unintentionally. Person B retaliates and harms Person A intentionally. Person A forgives Person B, without blaming himself, in order to end the harm.

The civility of humanity.

. . .

Person A harms Person B unintentionally. Person B sees that it was unintentional, and does not return the harm.

The magnanimity of humanity.

. . .

Person A harms Person B intentionally. Person C murders Person A, and anyone loosely affiliated with Person A.

Nearly every “hero” movie ever.