There is no such thing as fairness or unfairness. It is a line in the sand of human imagination drawn to motivate balance between equally imaginary parcels of the one true whole. Instead of engendering balance, thoughts of fairness or justice sometimes instigate war as one side imagines being deprived by the other.
"Reciprocity" can also be used as a club to beat the other into giving back. Such a demand needn't be verbalized; one can signal disapproval with the body, mood, or even more subtle ways.
Balance doesn't require justice. Balance just is. When a ball drops into a pool of water, the water splashes upward in a balanced response. Every moment is a moment of balance even while the quantities involved are still changing. Equilibrium is no more balanced than the movement toward equilibrium.
We may push forcefully to secure a certain outcome we consider fair. If worry accompanies the push, the outcome will likely bounce back the opposite direction. If the weight behind the push is greater than the either your hand or the object you're pushing, you will effect a more durable change. The largest weight is the weight of the world. Hence it is the complex interactions of the entire world that determine where the scales tip, not some man-made sense of fairness.
It would do us good to observe with humility the hugeness of the universe and let it determine how the galaxies and atoms should dance with each other. Atlas, let down your rock and let it roll.