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
What keeps me busy in my classes is trying to help my students learn how to think. They say, "Rob holds his hands like this...," and they don't know that the reason I hold my hands like this is not to make myself look that way. The end result is not to hold the gun that way; holding the gun that way is the end result of doing something else.
…The more general issue is that a person who doesn't understand the thing they're trying to copy will end up copying unimportant superficial aspects of what somebody else is doing and miss the fundamentals that drive the superficial aspects. This even happens when there are very detailed instructions. Although watching what other people do can accelerate learning, especially for beginners who have no idea what to do, there isn't a shortcut to understanding something deeply enough to facilitate doing it well that can be summed up in simple rules, like "omit needless words".