Practicing the golden mean
Most humans use intuition and feel their way to a decision. This behavior is often run on autopilot and does not lead to the practice of the golden mean. An untrained intuition is strongly affected by emotion and existing assumptions. Reason, the higher aspect in humans, must rule over the primary elements from the animalistic soul. However, the primary elements are not to be repressed or attempted to be removed; they must be acknowledged, accepted and channeled in the right direction. The golden mean, given enough practice, sharpens judgement and intuition.
Considering individual personalities
Aristotle was not unfamiliar with personality psychology; individual differences were taken into consideration in his thinking. This means that the golden mean will vary from situation to situation, and from person to person.
An individual with certain personality traits, for example high neuroticism (a reactive nervous system), will by nature have stronger emotional responses than a person that scores lower on the same trait. The brain of someone with the trait of high agreeableness will by nature experience conflict as more uncomfortable than a person scoring lower on agreeableness. This means that for the highly agreeable individual, it will be more difficult to have the confrontational conversation with the boss, as in the example above. Thus, in the real world, following the golden mean for this person will play out differently than for the individual scoring low on agreeableness.
A golden mean in the philosophical life?
Individuals with a higher score on the trait of openness/intellect are more willing to philosophize. They also value philosophy, art and abstract ideas to a higher degree than normal. Individuals scoring low on this trait does not find philosophy as naturally interesting; how should this person follow a golden mean? Such an individual does not necessarily need to understand all the theories and their details, but they can focus on how to practically apply the knowledge in their life. This is why Socrates argued for the importance of good education - a good education does not only give technical knowledge, but it improves human character and soul.
Here lies an assumption that the individual in the example values philosophical knowledge at all. Most individuals lack philosophical inclination, interest or even enlightenment; they do not see the value of philosophy in their own life. This was a tragedy for Nietzsche (and other philosophers), who ultimately thought that philosophy was only for elite human beings.
Socrates argued that the philosopher who claims, or actually has enlightenment, owed the ignorant people knowledge and education; this was the virtuous golden mean for the philosopher to follow. This would be an attempt to enlighten and improve any individual to reach their potential wherever they may find themselves on the journey of life.
Aristotle concluded that the philosophical life was the highest, most worthy life to live for a human being. This would be a life dedicated to knowledge, reflection and the development of one's soul. Political life came in 2nd place; this would be the practical life dedicated to improving society. Notice that the political life Aristotle talks about is not about focusing on one's career. Such a life falls into the next category. The lowest life was that of pleasure and hedonism. Pleasure can come through the senses, but also in the form of focusing solely on one's career, prestige, luxury and other activities that seek to please the animalistic soul.
Is there a golden mean here? The golden mean would not lead to suppressing the animalistic soul; such a force needs to be accepted and channeled correctly. The animalistic soul must be dominated and directed by the rational soul. Plato might have argued that the philosopher king would accept mild-moderate pleasure and participated in politics for the good of society (and not for furthering one's career or seeking prestige). This would be anchored in the highest human activity possible, namely philosophy. Those that do not want or can philosophize, should still focus on practicing virtue for the development of their own soul. Interestingly, human beings by instinct attempt to practice virtue every day. Most people are not aware that they have this project going on for themselves. Those with wisdom understand that within the human unconscious, virtue is considered the highest good. Humans intuitively value virtue in themselves and others. This conclusion should be reflected upon on a deeper level than evolutionary psychology.
"Down I went to the Piraeus..." -Socrates