I know the context of the PDF is a little different, but towards making the sentiment more broadly applicable, I'd suggest that an ability to own up to a mistake of any sort is a very useful professional "skill". Lacking that skill, it can be much more difficult to correct a problem before it becomes an issue (You hesitate, because a change implies the pre-change situation was "wrong") Once there's an issue, it also makes the cleanup much harder, more awkward, etc.
If you practice being comfortable saying something like, "I'm sorry, I overlooked X. I'm fixing it now, and will do my best to make sure it doesn't happen again" then your professional and personal life may be just a tad smoother. All of this implies, and requires, a mindset that is self-aware enough to evaluate itself. That can be the difficult part, that requires regular practice and resistance of instincts to go on the defensive and justify something, even if it was "right" at the time, if circumstances now show otherwise.