What's the most expensive satisfactory explanation you've ever accepted?

I'll go first. A service business. Stable revenue, consistent margins, high customer retention. No formal retention program. Why? The owner. Twenty years of relationships. Weekly calls. Problems solved before they became complaints. No system — just one person holding the customer base together through sheer attentiveness. The financials reflected his effort. They didn't reflect what happens when he leaves. What's one you've seen?