Immanuel Kant’s ethical theory of fairness requires that, for an action to be permissible, it must be possible to apply it to all people without a contradiction occurring.
The human psyche is strongly tended towards the idea of fairness. But life isn’t fair and many can’t accept this. Tolerating a little unfairness should be okay if it means greater fairness for all. We want things to balance but balance is not the order of life.