We have a new guy at work who loves unit tests. Yammers about them constantly.
If he's working on a feature that needs changes to classes A, B and C then his workflow is: make all the changes to class A, along with lots of unit tests. Then do the same for class B. Finally, do the same for class C. And then, after days of work during which the application doesn't even compile, he runs the integration tests and discovers that the application is broken.
Then someone comes over and rewrites his code so it works.
If he's working on a feature that needs changes to classes A, B and C then his workflow is: make all the changes to class A, along with lots of unit tests. Then do the same for class B. Finally, do the same for class C. And then, after days of work during which the application doesn't even compile, he runs the integration tests and discovers that the application is broken.
Then someone comes over and rewrites his code so it works.