Consumer behaviour is the study of individuals, groups, or organisations and all the activities associated with the purchase, use and disposal of goods and services. Consumer behaviour consists of how the consumer\'s emotions, attitudes, and preferences affect buying behaviour.The study of consumer behaviour formally investigates individual qualities such as demographics, personality lifestyles, and behavioural variables (such as usage rates, usage occasion, loyalty, brand advocacy, and willingness to provide referrals), in an attempt to understand people\'s wants and consumption patterns. Consumer behaviour also investigates on the influences on the consumer, from social groups such as family, friends, sports, and reference groups, to society in general (brand-influencers, opinion leaders). Research has shown that consumer behaviour is difficult to predict, even for experts in the field; however, new research methods, such as ethnography, consumer neuroscience, and machine learning[1] are shedding new light on how consumers make decisions. In addition, customer relationship management (CRM) databases have become an asset for the analysis of customer behaviour. The extensive data produced by these databases enables detailed examination of behavioural factors that contribute to customer re-purchase intentions, consumer retention, loyalty, and other behavioural intentions such as the willingness to provide positive referrals, become brand advocates, or engage in customer citizenship activities. Databases also assist in market segmentation, especially behavioural segmentation such as developing loyalty segments, which can be used to develop tightly targeted customised marketing strategies on a one-to-one basis. (Also see relationship marketing). Consumer behavior is how people feel and think when they are deciding whether to buy a product. In the study of consumer behavior, researchers might examine what people buy, when and how often they buy it, where they usually buy it, why they buy it .