A society's ability to adapt to changing outside parameters and to adjust its institutions determine the performance of its distribution system. In classical Greece, distribution had grown to such an extent that urban elite had no difficulties in consuming delicacies. Production of certain goods clearly exceeded local needs in some regions: Egypt, Sicily, and regions bordering the Black Sea, for instance, produced more grain than they consumed, Thasos, Chios, and the Chalcidice produced more and better wines than other parts of the Mediterranean. The Aegean connected people and the goods they needed. Transport was much easier by sea than overland. Moving goods by road required negotiations, protection money, and was impeded by deliberate obstructions, and outright violence. In classical Greece, many goods circulated through reciprocity, the mutual exchange between social equals. Friendship reduced transaction costs. On the revenue side, the interests of the citizens and the polis corresponded: both needed prosodoi, revenues or income.