You're not experiencing the world — you're experiencing your brain's best guess about the world, corrected after the fact. The feeling of certainty has nothing to do with accuracy.
When someone gives you advice, they are mostly describing themselves — their regrets, values, and the particular topology of their success. Learning to read advice this way doesn't make you cynical. It makes you a better filter.
We've been taught that envy is a character flaw to suppress. It isn't. Envy is one of the most precise signals your psychology produces — a direct readout of what you want and what you believe is possible. Suppressing it doesn't make you virtuous. It makes you less informed.