Despite my skepticism 6-7 years ago, about four years ago I became a big supporter and avocate of agile methodologies. But a key learning for me recently is that the success (measured by me as the ability for an agile methodology to adjust quickly to change with quality results) has more to do with the people involved than the processes they follow. While that is stating the obvious (I've always held the view that people are more important than process in software development, and my fondness of agile methods is due to their lightness on the process side), it does underscore my favorite line from Good to Great - People are not your company's most important asset... the right people are.
In my particular case, I'm observing an agile process cop actually execute agile (in this case Scrum) in a manner that resists change and slowing development down rather than expediting it. How to solve? Ah, that is the challenge I face, and I look forward to answering that question and blogging about it in the future!