I am kind of starting to doubt about the utility of unit tests. From a theoretical perspective I see the point in writing unit tests. But in practice I rarely seen them being useful. Guy A writes poor logic and sets in stone that poor logic by writing an unit test. Manual testing discovers a bug so guy B has to modify that poor logic and the unit test.

I'd rather see the need for integration tests and end to end tests. I want to test business logic not assert that 2 + 2 = 4.