Social groups are the main blocks of the society. The group is a set of people who are in mutual interaction, who share specific expectations and who take into consideration the other’s behaviours. In other words, social group is a set of people who share common goals and interests, who are interrelated and who have a continuous interaction for a while. For example, five people who are waiting for a bus at a bus stop do not consist a group. However, if they decide to take a cab and share the cab fare, they become a group and stay as a group until they get o the cab. Families, friends, students in a class, co-workers in a workplace are some examples of groups. The groups may be permanent or temporary. For instance, families are an example of the permanent groups and crowds are an example of the temporary groups.