TechCrunch writes about Evernote's Close Call: Just 3 Weeks of Cash Left During the 2008 Financial Crisis: "With two weeks left of funding, Libin made the painful decision to shut down Evernote and fire everyone.... But then something just short of a miracle happened. A passionate Evernote user [emphasis added] from Sweden dialed him up. He told Libin that he had been using the product for two months. He said it had changed his life — it had made him happier and more organized.... The user, who asked to remain unnamed, went on to offer some investment."
This is obviously an extreme example of a Happy Customer.
More importantly, focusing on Happy Customers helps drive the initial customer traction. Some related posts: