To build a folly is essentially to do something a second time, something at an inopportune moment. That something is always the memory of something forgotten, about which we can paradoxically say "There it is again."
Follies were misunderstood, purposeless constructions. They were often only small, extravagant gestures in a garden, easily whisking off the imagination to distant lands, a sort of time capsule built to awaken the memory and induce surprise in passers-by. They marked locations, organized secondary paths in a park, or simply predicted the arrival of better times—a demarcation, a sacred spot, a mysterious trail, a hill whose tragic rocky nature begged for a tower, a party, or the arrival of summer.
“It is demonstrably true that things cannot be other than as they are. For, everything having been made for a purpose, everything is necessarily for the best purpose.” — Professor Pangloss
On the surface, the world of agile software development is bright, since it is now mainstream. But the reality is troubling, because much of what is done is faux-agile, disregarding agile's values and principles. The three main challenges we should focus on are: fighting the Agile Industrial Complex and its habit of imposing process upon teams, raising the importance of technical excellence, and organizing our teams around products (rather than projects).
It actually doesn't matter whether you actually have a formal retrospective. It doesn't matter whether you have four or five labels of things on your retro board, or exactly how you do the retro. What does matter is the notion of thinking about what we're doing and how we can do better, and it is the team that's doing the work that does this, that is the central thing.
Interestingly, just as software people were talking about how we need to kind of follow this very Taylorist notion as the future of software development, the manufacturing world was moving away from it. The whole notion of what was going on in a lot in manufacturing places was the people doing the work need to have much more of a say in this because they actually see what's happening.