What Makes Opportunity Cost Important?

Opportunity cost is an important element in  maximising social benefit. Suppose there are two agents deciding whether or not to commit to a transaction, each agent will want to maximise their potential benefit given their constraints. For example, a consumer may want to maximise their utility whilst the producer wants to maximise their profit. An important factor in this constraint will be the next best return on the funds that will be devoted to the transaction; the opportunity cost. If either agent can earn a better return by allocating their resources elsewhere then there remains the capacity for further trading between the agents exists (i.e. They should change the terms of the transaction) or else the agent should invest his resources where the return is the highest. If the opportunity cost of resources is not taken into account inefficient allocations of resources will be made, which is costly to society.