I doubt anyone reasonable even claims that a perfect society is possible - someone will always feel wronged regardless of their circumstance. I don't think it's unfair to say that the main function of a society is to reduce the likelihood that a person of said society gets wronged. Which brings the question of how does a society do that without enforcement of laws? If we accept the NAP is a law, who reprimands those who break it? Who actually defines what it is in the first place? Undoubtedly there are many different interpretations of it and it's not possible to achieve a feeling of fairness in a society if not everyone agrees on its basic structure and laws. If you feel like these are too basic of questions, feel free to link me to what you would consider a definitive explanation.