Identify a system you have built or worked on where the actual usage pattern differed from the intended one. What architectural assumption was exposed? How long did it take to detect the discrepancy?
For a product you currently work on, list three technical metrics you track and three user outcome metrics. How are they related? Is it possible to improve the technical metrics while degrading the user outcomes?
How would you explain to an engineering team that 99.9% uptime on a product with 0% user adoption is not a good engineering outcome? What measurement system would you propose instead?
The chapter argues that users are the external input to the system and that their behaviour is variable and unpredictable. What design principles follow from treating users as an uncertain external signal rather than as a predictable fixed input?