Yesterday I had to do something somewhat unpleasant - I had to call somebody working for me on his absent behavior.
It might not be easy for many people to believe, but this can be quite stressful for the manager.
This would not be an issue if the person in question was producing well; we are, after all professionals and are inclined to give a degree of slack. However, this person's basically not very productive, and even though these absences are glaringly apparent to everyone around, and even though everyone else is being short-changed by this person's absence, it is still somewhat stressful to have to confront someone this way, even when you're basically "following the algorithm" that is used specifically for such issues.
In such moments, practicing "just this" as far as the disciplinary procedure is essential- especially when at the same time your more primitive areas of the brain might be suggesting a less civilized response.