This report delves into the realm of organisational behaviour, examining the dynamics of effective and ineffective teams, with a specific focus on the retail giant Tesco. It explores the critical elements that shape human behaviour in the workplace, including team development theories such as Tuckman's stages and Belbin's typology, alongside the application of Janis's theory. The report analyzes how these theories contribute to fostering cooperation and achieving organisational goals. Furthermore, it investigates various concepts and philosophies of organisational behaviour, such as the Path-Goal Theory, social capital theory, and contingency theory, assessing their positive and negative impacts on behaviour. The analysis evaluates the relevance of team development theories and leadership styles, concluding with insights into how Tesco utilizes these concepts to enhance team performance and achieve its objectives.