Goods may increase or decrease their utility directly or indirectly and may be described as having marginal utility. Some things are useful, but not scarce enough to have monetary value, such as the Earth's atmosphere, these are referred to as 'free goods'.
In economics, a bad is the opposite of a good. Ultimately, whether an object is a good or a bad depends on each individual consumer and therefore, it is important to realize that not all goods are good all the time and not all goods are goods to all people.