Rob. you send my down the path of unit tests, and it really did change everything I knew about programming. For me, I think collaborating with someone brings out some very interesting implications of tests. Its incredibly eye-opening to work with code someone else wrote and you wonder “this could benefit from a change” and *actually be able to change that code*. Or someone wonders about your code in an edgecase you didn’t think of, and a test instantly shows if there’s a problem or not. Having true confidence in code is worth everything, and it starts with unit tests.