The document discusses the importance of engaging with customers when raising capital for a startup. It notes that having customers can help improve a startup's chances of achieving milestones that are critical for attracting investment. Customers will provide feedback on whether the product concept makes sense and if the product works. Engaging with customers early allows startups to learn how to build relationships, develop trust, and weather growing pains. Customers can also serve as referrals for future customers and provide revenue, which demonstrates the value proposition and attracts investors. Both startups and investors see customer relationships as rewarding.