The crux of The 3 Mistakes of My Life by Chetan Bhagat revolves around the story of three friends—Govind, Ishaan, and Omi—who live in Ahmedabad and navigate the complexities of friendship, ambition, love, and the challenges posed by socio-political and religious tensions in India.

The novel is structured around the idea of "three mistakes," which are significant decisions made by the protagonist, Govind, that change the course of his life and the lives of his friends. These mistakes are:

1. A Business Decision: Govind’s first mistake is a business decision that initially seems profitable but leads to unforeseen consequences, affecting both his financial stability and the dynamics between the friends.
2. A Relationship Mistake: The second mistake involves a romantic relationship that results in complicated emotional and social repercussions, challenging the friendship between the main characters and pushing the limits of loyalty and trust.
3. A Political Choice: The third mistake is tied to the involvement in a politically motivated situation that spirals out of control, leading to violent and tragic outcomes that significantly impact the lives of the characters and the community around them.

The book explores themes such as ambition, friendship, love, sacrifice, and the harsh realities of life in a rapidly changing society. It highlights the impact of personal decisions against the backdrop of larger social and political issues, such as communal tension and economic inequality.

At its core, The 3 Mistakes of My Life is a story about growth, redemption, and the search for meaning amidst the chaos and struggles of life. It encourages readers to reflect on their choices, learn from mistakes, and understand that life's challenges can lead to personal growth and resilience.