Public goods problems refer to the difficulties that arise when a good is non-excludable and non-rivalrous, meaning that individuals cannot be effectively excluded from using the good, and one person's use does not diminish its availability to others. These characteristics often lead to underproduction or overconsumption of public goods, as individuals may opt not to contribute to their provision while still benefiting from them. This situation poses significant challenges for economies, as it can result in inefficiencies and require government intervention or collective action to resolve.