How would you convince someone that the concept of "fairness" is an important one

Although "fairness" is not a well known or well justified concept in this day and age, it is an incredibly important one. If things weren't "fair" then convicted felons/murderers would never be caught. Abusive men or women would never be punished for hurting their significant other. Children in foster care or orphanages would never find proper homes. If things weren't at least the slightest bit fair then nothing would ever work in the favor of your or the next person.