Bad (sometimes "Bads") is an economic concept that refers to harmful economic products that cause more harm than good and thus result in negative utility.[1] They are therefore the opposite of goods. Many economic bads are negative externalities like pollution or traffic congestion. However, some bads may be products that people buy that have harmful effects on their own health like illegal drugs, unhealthy food, or legal drugs like tobacco or alcohol. Many economic bads sold illegally in black markets are not measured in conventional national income accounts like gross domestic product.