The real reason I want to be five years old again

Each of us is born with an epigenetic program that has been fine-tuned by tens of millennia of hunter-gatherer subsistence living.  The proper unfolding of our innate maturational design requires carefully timed environmental input (from both the social and the natural environment—although our DNA does not recognize the distinction), input that reflects patterns of life in largely egalitarian band society. 

Part of this developmental unfolding involves the freedom to form and pursue age- and culture-appropriate goals—authentic human goals.  Civilization is successful as a machine for directing and coordinating human activity precisely to the extent that it is able to usurp this process and entrain our behavior to goals that are not of our choosing.   The subtle ways that it accomplishes this is perhaps subject matter for another rant, but the first step involves the disruption and distortion of our natural maturational programming.

The artificial social hierarchies of civilization need to be enforced at an early age in order to prevent our evolved anarchist tendencies from getting a solid foothold.  Children have to be forced to keep their natural proclivities in check, to respect and obey authority—to stand in line and wait their turn.  Those who resist are labeled (e.g., ADHD) and medicated into submission.  Once passively in the queue, the demands and expectations of modern civilized life squeeze naturally cyclical developmental processes into a linear timeline, leading to the incomplete or truncated maturation of key psychological systems and capacities that are needed for the successful future maturation of later-developing systems and capacities.   

Imagine trying to install the roof on a house where the foundation has not been completely poured and several of the walls are missing.

As civilized adults, we are all incomplete, malformed human beings.  According to Paul Shepard, nostalgia for our childhood years is not just a desire to return to a time when life was simpler.  It reflects our deep desire to return to a time when we still had the potential to develop into complete human beings, a time when it was still theoretically possible to realize our authentic human design.