Because the inner characteristics that constitute an individual's personality are a unique combination of factors, no two individuals are exactly alike. Nevertheless, many individuals tend to be similar in terms of a single personality characteristic. For instance, many people can be described as "high" in sociability (the degree of interest they display in social or group activities), while others can be described as "low" in sociability. Personality is a useful concept because it enables us to categorize consumers into different groups on the basic of a single trait or a few traits.