Warren Buffett's youngest son Peter Buffett made one of the most talked-about financial decisions in modern personal-finance history. In 1977, at age 19, Peter inherited $90,000 in Berkshire Hathaway stock proceeds from the sale of his grandfather's farm that his father Warren had converted into Berkshire shares. Peter sold all of it. He dropped out of Stanford, moved to San Francisco, bought recording equipment, and set out to build a career in music. Warren Buffett made it clear from the start: this was Peter's only personal inheritance. No trust fund. No ongoing financial cushion. If Peter had held those Berkshire shares instead of selling them, they would be worth around $500 million today based on Berkshire Hathaway's current share price, which recently traded above $774,000 per Class A share. Peter has said in interviews and in his 2010 memoir "Life Is What You Make It: Find Your Own Path to Fulfillment" that he does not regret the decision for a moment. In his own words, "I used...