Why don’t software development methodologies work?
It's fun to watch observations like the following re-discovered again and again. From the NATO Software Engineering Conference in 1968:Ross: The most deadly thing in software is the concept, which almost universally seems to be followed, that you are going to specify what you are going to do, and then do it. And that is where most of our troubles come from.Fraser: One of the problems that is central to the software production process is to identify the nature of progress and 
to find some way of measuring it. Only one thing seems to be clear just now. It is that program construction is 
not always a simple progression in which each act of assembly represents a distinct forward step and that the 
final product can be described simply as the sum of many sub-assemblies.(Full transcript of the 1968 conference here. http://homepages.cs.ncl.ac.uk/brian.randell/NATO/nato1968.PD... It's a really fun read!)