And if a tool is that difficult to use, how can you tell if the problem is in the tool or the user? There's a large industry built around doing training and certifications in agile methodologies now. If a tool is that difficult to get right, maybe it's just not a good tool to begin with.

To be fair, the manifesto and methodology is quite good in theory. But I just have never heard of(or experienced) it working properly and the response is always that it wasn't implemented correctly.