Kristoff's core thesis on using RSpec correctly. To turn tests into true specs (tests written for humans), teams must leverage RSpec's built-ins — custom matchers, helper DSLs, and shared examples. Example: a matcher that asserts an operation returns a decorated object; higher-level helpers that read as 'I'm stubbing a policy, I'm stubbing a service'. Techniques like 'with every combination' remove 200-line manual cases or awkward sample/collection loops and produce better failure messages. Without this discipline, teams end up writing tests with RSpec that would be cleaner as minitest or testbench.