Final answer:
Consumers are better off not consuming an additional good or service if the marginal cost is greater than the marginal benefit.
Step-by-step explanation:
A rational consumer would only purchase additional units of some product as long as the marginal utility exceeds the opportunity cost. As a person consumes more of a good or service, the additional satisfaction or benefit they receive from each additional unit, known as marginal utility, decreases.
At the same time, the opportunity cost of consuming that additional unit, in terms of giving up alternative goods or services, increases. Therefore, when the marginal cost is greater than the marginal benefit, individuals are better off not consuming an additional good or service.
For example, if someone has already eaten two slices of pizza and they are considering eating a third slice, the additional satisfaction from the third slice may not be as high as the first two slices.
At the same time, the opportunity cost of eating that third slice, in terms of the satisfaction they could get from eating a different food item or saving that slice for later, may be higher.
So, if the marginal cost of eating the third slice outweighs the marginal benefit, the person would be better off not consuming an additional slice.