What happened to my test coverage?
Writing code feels so much easier than writing tests for it, and does that one-line method really need to be tested, anyway? But soon, your code is only 20% covered by tests, and any change you make to your code feels like trying to replace the middle layer of a house of cards without knocking the whole thing over. This isn’t a skill failure. It’s a process failure. With a few changes in how you write new features, you can protect your code without your tests slowing you down.