Lessons about efficiency and fairness:
-When one person or group has the power to dictate the allocation, subject only to not making the other party worse off than in their reservation option, the powerful party will capture the entire surplus. If they have done this, then there cannot be any way to make either of them better off without making the other worse off. So this must be Pareto efficient.
-Those who consider their treatment unfair often have some power to influence the outcome through legislation and other political means, and the result may be a fairer distribution in their eyes or ours, but mat not necessarily be Pareto-efficient
-If we have institutions under which people jointly deliberate, agree on, and enforce alternative allocations, then it may be possible to avoid the trade off and achieve both efficiency and fairness