Philosophical clarity with atheistic pessimism for diagnosing unhappiness

I was talking with my wise yet controversial friend Helen whose real life stories I used to blog in another site but stopped with her final request. Even though she is very young (at her early twenties), Helen looks at things from multiple angles and has vast knowledge of philosophy and human psychology within sociological context with the practical sharpness. Her capabilities even challenge her father's many years of academic and corporate experience in dealing with a number of life situations.

When I asked Helen about recent issues related to her father, she diagnosed her father's recent unhappiness with two words (boredom and pain)which later I found borrowed from Arthur Schopenhauer who is known with his atheistic pessimism and philosophical clarity. She said Bruce was recently unhappy due to excessive boredom at emotional and severe pain at physical level.

First it was hard to conceptualize the scope of these two words and interrelationship for one's unhappiness within such complexity. When she gave me a number of examples related to her father's situation with thirst of unfulfilled material desires and link to our previous discussion on whether reason alone can unlock key answers about the world, I started seeing an unexpected yet pleasant light upon a dark issue in my perceived world too.

It was easier to relate to Helen's challenging thoughts as I used to read theories of Schopenhauer's in my early twenties as well. It was inspiring to understand views of an aesthetic pessimist relating to teachings of well known Buddhist, Vedanta and ancient Greek Stoic philosophers. And more importantly, Schopenhaeur always reflected something familiar for me with the intellectual and emotional taste of my favourite thought leaders like Nietzsche, Freud, Jung, Borges, Wagner, Camus, Wittgenstein, Schrödinger, Einstein, and more...And his philosophical clarity was evident with sharp and wise remarks like "The more unintelligent a man is, the less mysterious existence seems to him” or metaphorically "Wealth is like sea-water; the more we drink, the thirstier we become; and the same is true of fame.”

I learnt through Schopenhauer's analysis that emotional, physical, and sexual desires can never be fulfilled! And it was amazing how empowering to have such a fundamental yet powerful piece of knowledge in early twenties which may even shed lights on senior citizens' complex issues.

What kind of privileged knowledge or insights have you obtained at your younger ages which you still use in your life for enlightenment or other purposes of your life?