Yak shaving

I have found this Yak Shaving to be true in many occasions, especially when starting the BuildMaster project.

I think that is why Agile development works. You use one iteration to focus on one level of the work to build a "Walking Skeleton" as described in "Crystal Clear". At the same time, you keep updating the story backlog about all the work that you discovered on the way so that you don't lose anything and can prepare for future iterations at the same time.