When guidelines contradict each other. You need a proper way to communicate where a piece of code stands.

Indeed, don't mindlessly add tests. I find interesting that the doubts raised in this piece are once again concluded using an old quote of Kent Beck. What he was proposing was fine and then over time people became clearly unreasonable.

Indeed this. It's not only about payload size, it's also about CPU consumption. Our profession is still assuming too much that users will get faster CPU on a regular basis.