After my wife and I bought a house a few years ago that dates from the beginning of the 20th century, our interactions with pipe fitters, roofers, carpenters and the likes of them showed a dramatic increase in its frequency. At first we were invariably put of our rocks by them, because every single one of them claimed that things were not at all right and that the roofer / pipe fitter / gasman before them had made a mess of it. Some of them showing in detail what was wrong.
Gradually however, we came to recognize the pattern and today we don't expect them to say anything else. Apparently, it is a culture thing of the artisan: Start by asserting yourself as better qualified than your predecessor by disparaging his work.
Now, I was not aware of the same culture of disparagement associated with other professions, until lately I started recognizing the same pattern at the company that I work for. I work as a software requirements engineer and have to talk a lot with software engineers. Because of changes in our company related to off- and re-shoring, quite a lot of the software engineers have lately gotten different software modules to work on. And lo, when the informal talk about the software starts, every single one of them starts criticizing the way the module has been programmed by their predecessor(s)! The structure is not set up in a correct way, there's to much redundant coding, there's unnecessary coding because of features of the development tool etc. Better to recode the stuff boy, if not in a grand way (making a project out of it and getting a budget for it), then at least in a piecemeal way and doing it in secret. And if you are an intellectual, just call it refactoring!
Here's what Martin 'refactor' Fowler has to say about it in his book on the subject: "However, I find that if I refactor code, I work deeply on understanding what the code does (...)"
So, what is going on here? For - to be honest with you, and as I became aware of lately - of course I tend to do the same. When I have to work on a functional design document written by someone else, i sure as hell start criticizing it and edit lots of it: its structure, its wording, its mark-up, nothing is sacred. And in the course of tinkering with the document it becomes my document, not in the possessive sense but as something that i'm familiar with, of which i recognize the particular idiosyncrasies, of which i know the meaning of all its details.
By now and if you are familiar with it, you will recognize processes that Heidegger and Michael Polanyi describe. In 'refactoring' the document i'm 'indwelling' in it, it enables me to know the document in a very personal way. And to wit: that is the only way of knowing it.