Be a pragmatist rather than a purist when it comes to management methodologies and frameworks. Such things are means to an end, not ends in themselves. I’ll happily mix and match bits and pieces from different approaches, such as PMBOK and agile, as long as they are effective for the situation I’m in. That’s why I’m encouraged by the rising interest in hybrid frameworks, which mix predictive and agile project management within the same organization and sometimes even on the same project.