I have often used the phrase "Best Practice" to bolster my opinion about a technical approach, or been swayed by someone else's use of the term. There's probably a blog post worth of ranting about that on its own, but for now, I'd like to talk about diverging from "Best Practice".
The idea is that there is a set of "best" ways to do something, solve a given challenge, or handle some situation. I think it's important to draw a distinction here, though -- these practices are not the best because they're necessarily the best suited for every situation. These so-called best practices are usually the most widely accepted, officially approved, or initially intended approach.
Best Practices are often ignorant of context. Granted... they're usually still the best idea in most contexts; however, they shouldn't be applied blindly. Even if you're convinced you should adhere to a best practice, you should know why you are choosing to do so. What benefits does the approach offer? Why is it better than alternatives?
Asking these types of questions (and writing down their answers!) is a great way to always be clear on when and why you decide not to adhere to a best practice. Choosing to shirk best practice isn't an engineering sin... as long as you have good, documented, rational reasons. Like... really good reasons!