In a counterintuitive conclusion, product teams are found to work best without a single leader, leveraging the psychological principle of diffusion of responsibility, which explains that groups tend to do less when ambiguity of responsibility arises. In contrast, having a clear leader is effective in meetings and projects, as it promotes accountability and ownership. However, product teams, with their ambiguous leadership structure, can thrive without a single leader due to the partnership between engineering manager, product manager, and designer, which requires trust, humility, and daily effective communication.