To convince ourselves (and others) that our actions are justified, we say things like, “This is going to hurt me more than it’s going to hurt you,” “It’s for your own good,” I had to teach him a lesson,” “She had it coming,” I had no other choice,” “I couldn’t help myself,” “There was nothing I could do,” “It was the right thing to do,” “The end justifies the means,” etc. Each of these statements tries to imply that even though feeling says this is wrong, reason makes a stronger case that it is right (or vice versa).
Whenever the “proper” response is unclear, the legitimacy of our actions is open to interpretation. If there were a way to stand outside of it all and take a truly objective view, we could see absolutely which actions were justifiable and which were not. Unfortunately, we are not afforded this objective view in real life. So, we create stories to try and approximate the objective truth.