I've worked within organizations that told themselves that some best practice widely promoted throughout the industry cannot possibly be applied at this organization, because this organization's work is "special". Our code isn't like other code. Our customers aren't like other customers. Our problems aren't like other companies problems, so this commonsense rule does not apply to us (and therefore we need not change our practice).
When I had the evangelical furvor of the rookie, this behavior made me wild. It was clear to me that there was absolutely nothing special about our code, and that industry best practices got to be best practices exactly because they were widely applicable. I came to understand that the purpose of the word "special" in this conversation was to defeat any kind of reasoned argument, any comparison or evidence, and defend the status quo.
When I became an old hand (and by that I mean, as I was typing this blog entry after facing this anti-pattern yet again), I realized something else. I realized that "special" was the antidote to the phrase "best practice", which itself is meant to defeat argument without presenting evidence.
When you find yourself in such a conversation, it means that both sides have staked out a position that they are too lazy to defend with any actual evidence. To make any progress you must change the conversation. Perhaps, "Best practice X will improve our results in thus-and-such a way.", or, "Practice P is being used successfully by our own competitors." This raises the level of the conversation so that the other stakeholders must argue specifically against your evidence. When they say "special", you can then say, "Yes, but in what way does our special-ness invalidate the evidence?"
It is tedious to argue from evidence, and easy to resort to words like "special" and "best practice". However, the comversation generally goes better if you come prepared with some actual data.