A young man, having just entered society, felt lost and directionless. He longed to understand the "secret of life." Someone told him that a wise man knew this secret.
So, he went to visit the sage. Upon hearing his intention, the sage said, "I have six words for your secret to life. I will give you three now, and the other three later." The sage then wrote three words on a piece of paper, placed them in an envelope, and told the young man to take them home and open them later.
When the young man got home and opened the envelope, the words were: "Do not fear." He took these three words as his motto and began to strive for success. By middle age, he had achieved some success in his career and had a wife and children, but he still felt a sense of emptiness within...
He thought of the sage again and went to ask for the remaining three words. However, the sage's family told him that the wise man had passed away several years ago. As the young man was about to leave in disappointment, a family member suddenly asked, "Are you XXX?" The young man replied, "Yes." The family member said, "He left a letter for you before he passed away."
When the young man returned home and opened the letter, it contained the final three words: "Do not regret."