I've made a series of test stories from my favorite test runs. During this test run I used the method of user experience mapping to show how a target groups satisfaction with a product changed as they interacted with it, thereby finding problem areas for redesign.
Last month I did a one-week project where I put an app through usability testing. The company that hired me was very careful not to tell me a lot about the app and their system, since they wanted me to see it for the first time. That was a very wise decision on their part. While I performed the first testing, and got to know the app, I was struck with the value of this very first meeting with the system.