Pinterest, despite its massive user base and high valuation, is intentionally designed to appear as a work-in-progress, fostering a culture of continuous growth and innovation. John Egan, an engineering manager at Pinterest, emphasizes the importance of viewing growth as a dynamic and evolving process, with engineers playing a crucial role in devising creative solutions to enhance user engagement. Egan's journey from launching a startup in San Diego to contributing to the development of Shopkick's growth team highlights the significance of integrating product thinking, engineering, and user psychology. This approach has been instrumental in driving significant improvements in user acquisition and engagement. At Pinterest, engineers are encouraged to take ownership of projects and experiment with innovative ideas, exemplified by an engineer's successful optimization of email subject lines, resulting in a substantial increase in open rates. Egan advocates for a growth engineering culture where engineers are empowered to think strategically and creatively, suggesting that even smaller startups can benefit from fostering such an environment to drive impactful growth.