This report provides a comprehensive analysis of consumer behavior and insight, focusing on the customer decision-making process. It begins with an introduction to consumer behavior and its importance, followed by an examination of the stages involved in the customer decision-making journey for a product, using Marks and Spencer as a case study. The report then explores why it's essential for marketers to understand and map the customer's buying journey. It differentiates between B2C and B2B decision-making methods, evaluating various market research theories and methodologies used in both contexts. Furthermore, the report analyzes how companies can influence the different phases of the decision-making process in both B2C and B2B scenarios, including the impact of culture, subculture, and opinion leaders. The report concludes by summarizing the key findings and implications for marketers aiming to understand and influence consumer behavior effectively.