airness, justice, revenge, avenge, venge. They aren't synonyms. Eye for an eye isn't justice, especially when those who think they know better are involved. It's revenge, it's the petty beginning of a war. One person gets punched, they punch back, it seems uncomplicated, fair. But then the first puncher forgets their misdemeanor, and punches back even harder in righteous retaliation. Suddenly it's not simple at all. Should the punched not defend themselves to avoid this, or is it the fault of the first puncher? It's not as clear a question as it should be. It only takes one side to escalate small problems into a uncontrollable and bitter feud. On a larger scale, it can cause the death of millions. A dead aristocrat turns into World War One, a land dispute turns into the Middle East, an orphan turns into Lord Voldemort. Talking could easily fix the entire situation, but why talk about our feelings like civilised people when we have fists, and knives, and guns, and nuclear bombs (and Avada Kedavra)?
You happen to like the same girl as the school Quidditch champion, or you turn down the friendship of a blonde rodent, or perhaps, you just happen to have helped a friendly redecoration committee. They feel threatened, slighted, and ready for petty revenge. Before you know it, you're hanging upside down in the air being called names, being tricked into illegal midnight duels, being turned into a ferret by a prefect. You resent this person who is taking the situation way out of proportion, and take defensive measures. You might join a group that promises protection, or cause mischief and havoc for your tormentor, or even sneak back into their room and give it a nice ferret theme (complete with the adorable animals themselves) for a peace offering. But your defenses are in vain: the bully gets the girl and you are now a criminal, the rodent intently destroys the lives of your friends and hippogriff, and the prefect doesn't appreciate the gift. Of course, you get the better deal eventually, even if it's not what you wanted. You die a bigger hero and the bigger person, and save way more people than your enemy, as well as being a much more complex character and appearing way more often. The rodent never bothers you again after you save his and his family's lives. And after trashing the broom cupboard and make it look like the Prefect, you bring an offering of high-quality caffeine to the Heads of House without knowing anything about the missing brooms.
Vengeance is petty. Justice cannot ever be made that way.
But revenge is still best served cold, and as success or a non-permanent and non-serious punishment.
I hate being turned into a ferret.