Revenge. We see it played out constantly in books, television shows, and movies. When someone wrongs you, you wrong them back, sometimes worse than they did in the first place, just to make sure they learn their lesson. We are groomed to think that this somehow makes things fair and that we are justified in inflicting this "punishment." However, doesn't this form of "punishment" just make us the same as them. If we kill someone because they killed someone else, does that not equate us to their level. I am not saying that people should not be punished for the crimes they commit, but there are different forms of punishment.
If people continue to destroy each other in an attempt of seeking justice or making themselves feel better for the pain they have suffered, no one will be able to grow. We get so caught up in trying to get revenge that we forget to learn from the experience and we don't allow the other person to grow either. Any sort of change or revelation that could've been part of the healing is caught in the crossfire of an unnecessary war.
It is also a waste of our time to be upset and plotting when instead this time could go to helping people in situations similar to yours or getting justice in a more positive way. We tear each other down when we follow the philosophy of "an eye for an eye." To rise up and better the lives of others who have been wronged is the only way we can bring positive change into the world. The revenge mentality keeps us in our own little bubble of pain and perpetuates the violence that hurt us in the first place.
All of what I have said is not an easy thing to do and does not come quickly, but we must have the patience to try. If we don't we will continue to live in a world of hate.