The Anna Karenina Principle, technically speaking
Tolstoy informs us, by way of his novel Anna Karenina, that every happy family is alike, while unhappy families are unhappy in their own special way.
Applying this to technology, best practices are that happy family of techniques and patterns, processes and methodology which have proven successful at a wide variety of companies, for a wide variety of applications.
A software developer well-versed in best practice knows what to expect anywhere else best practices are implemented.
Conversely, the further from best practice, the more “special sauce” a developer will have to master to become effective.