At around two years of age, we create the idea of a "self" that is separate from other people & everything else ("individuation").
With a "quiet ego" the individual can competently pursue meaningful short- & long-term goals, equally valued by herself (appropriate self-care), society (allocentric), and the natural world (ecocentric). This self-concept & associated worldview appears to be optimal, and in fact is one secular definition of "wisdom." Exemplars include wise, loving grandparents; the many "unsung heroes" - solid, decent, completely trustworthy people who quietly go about their business without ever drawing attention to themselves; mystics & saints.
With a "noisy ego" the individual is primarily driven by self-concern, disregarding the welfare of others & the environment. This is the opposite end of the spectrum. The most extreme form of this is Antisocial Personality Disorder, exemplified by amoral political & business leaders, serial killers etc.
As we mature, our egos naturally tend to quieten, as we become somewhat less rigidly, fearfully self-centered, and become increasingly outwardly-focused, generous, concerned for the welfare of others & the natural world. This shift in self-concept & worldview is markedly disrupted, or even prevented by attachment injury & other forms of major trauma. Profound transformation from a somewhat fearful "me-alone-against-a-hostile-world" identity, towards an open mind-hearted, loving, nurturing embrace of everyone & everything - of life itself, is normally slow, gradual & tentative even if we were spared from major trauma, and even if we're working towards this full-time (eg as a monk or nun).
Perhaps the ultimate level of psychosocialspiritual evolution is "awakening" or "enlightenment" - the Zen understanding of "wisdom." Enlightenment has been defined as "intimacy with all things."
Buddhist meditation practice is one of a number of ways to achieve this clarity of experiential understanding of ultimate reality. Regardless of one's chosen path of maturation - another wisdom tradition or a purely secular path - I suspect that the profound shift in self-concept & worldview is key. Given the disturbing prevalence of major trauma, many of us need psychotherapy to allow this shift to happen at all. Instead of merely "getting by," we then have the chance to flourish, expressing our full human potential.
“When we sit in meditation, we can discover a way of being that is very different from our typical interactions with the world. For the period of time that we sit, we agree within ourselves to quiet the familiar internal chatter that goes on most of the time. We sit so that we can discover in ourselves this capability for stillness, for intimacy with our self. We can uncover the heart.
This process of stilling the mind and opening the heart brings a great feeling of ease that courses through the body, releasing the sensation of holding back, of fragility or tightness, and freeing us to work with the challenges of life. I call that true intimacy. When we can actually feel what we are feeling, experience what we are experiencing, and recognize what we are thinking, then we become intimate with ourselves. This intimacy is a closeness, a quality of interiority, a nearness. To be intimate with yourself is to be so attuned to your own feeling-state and mind-state and perception-state that nothing is hidden, your whole being is available to your life. In this intimacy with self, we begin to recognize the habits of thinking that stop us from living confidently, generously, and vigorously. And we begin to trust ourselves.
... To me, intimacy is the underlying liberation of Zen. When I talk about intimacy, I’m talking first about intimacy with ourselves, then about intimacy with our lovers, partners, and close friends. I’m talking about intimacy with the work we do and the colleagues with whom we work, intimacy with our community and with the great earth – intimacy with everyone.”
Roshi Pat Enkyo O’Hara. “Most Intimate. A Zen Approach to Life’s Challenges.” Shambhala, 2014.