The study of Religion can broaden your understanding of different types of people in the world around you, and can introduce you to spiritual ideas that might be a path for your own life. It can also teach you to understand and respect other cultures and beliefs, which can help in connecting with your family, friends, and co-workers.
It is common today to take the concept religion as a taxon for sets of social practices, a kind of category whose paradigmatic examples are the so-called “world religions” of Judaism, Christianity, Islam, Hinduism, and Buddhism. These kinds of definitions are called “monothetic” because they impose on their subjects the notion that each instance can be accurately described by a defining property that distinguishes it from other instances.
But this assumption is flawed, as the anthropological research of Charles Muller and others has shown. The emergence of social kinds does not wait on the development of language, and in fact many social realities have never been adequately defined by any sort of lexical or real definition.
A more promising approach is the “polythetic” model, whereby each instance can be classified as a member of a class in terms of the presence or absence of certain features. For example, Emile Durkheim’s functional definition of religion includes all of the activities that unite a group of people into a moral community (whether or not those practices involve belief in unusual realities). Alternatively, as Rodney Needham points out, one can use a computer program to sort different kinds of bacteria according to their properties.