You've seen this codebase. 400 tests, all green, and nobody trusts any of them. The coverage number looks great in the CI dashboard, but developers still test manually before merging because they've been burned.

It happens gradually. Someone mocks the database. Someone else mocks the HTTP client. A third person mocks the service layer. Now you have a test that verifies your mocks return what you told them to return. It passes when the real system is broken. It fails when you rename a method. It tests nothing and breaks constantly.

The fix isn't "more tests" or "100% coverage." It's fewer, better tests. How? Let's talk.