Grow up in the sense of being able to react coolly to provocation instead of jumping the gun. If you take a person's provocation badly, that means the person is getting what they want, they are winding you up. Ie. you are losing control and the aggressor is now in control of your actions, just by adjusting the provocation levels. If you're dealing with someone very patient and vindictive, this can go on for quite a while. Whereas if you show no interest in provocation, the other person will soon quit and leave you alone because they're getting nowhere.
And above that, an eye for an eye was ingenious and applicable in the stone age, we've moved on from that. Or at least we like to think that we have.