Completed large refactor in my software. Intermediate data can now be formulated as one of two different data structures. Unit tests updated to test both formulations for each test case, effectively doubling the number of test cases.
Run unit tests… and… 100% tests pass.
Younger version of me: “YES!!! I am a hacker god!”
Current version of me: “WTF!!! There is no fucking way EVERY – SINGLE – LAST test case just passed after all that refactoring.”