The basic problem with the Agile movement is that it took a few
proven helpful practices -- almost all of which were well known and
often used by experienced software developers before the buzzwords
were attached, even if managers didn't realise -- and instead of
promoting those, it wrote a "manifesto" so vague that it would make
a political speechwriter proud, which didn't actually say anything at
all about the practical steps that were useful.
Avoiding creating a list of helpful practices was by design. The signatories of the Agile Manifesto were all very seasoned developers, and like all seasoned developers they knew that a practice that helps in one case harms in another.
You can kind of see how it might go wrong from there:
* Seasoned developer makes list of helpful practices,
without providing context, i.e. "Helps in this case,
harms in this case."
* Unseasoned developer doesn't understand when and where
practice is "helpful", tries to use it in all and every
case. Sometimes it works, sometimes it fails.
* Unseasoned developer who complains: "Helpful practice X
didn't work for me" is told "You're doing it wrong."
Again, no explanation of when and where the practice is
helpful is provided.
The takeaway here is to always, always, ALWAYS describe the context when describing a solution, i.e. "This is what worked for me, in this situation."