When people think about justice, then, they want revenge . If one don't get even with that person, the emotional pain won't go away. However, from a Taoist / Buddhist point of view, if one can just let it go and don't think about justice, then, the pain will go away. No matter what the situation is, one always keep one's poise and emotionless. Just treat like it is none of your business. One cannot change whatever had been happened already and can't do anything about it, then, just let it go. That is what cultivation of the mind was all about. Perhaps, this is not something that a normal person can handle. Peace!