It is so *avoidable*. Customers who silently vanish, members who unsubscribe without reason, students who don't return for your next course, clients who disengage. In this era of exponential abundance of customer choices, it is simply not enough to have "satisfied" customers. You must learn The 9 Principles of Customer Feedback - the rarely used psychological secrets - that will engage, retain and delight your people, creating a gravitational pull ensuring they will never leave you.