Mark Twain, the pen name of Samuel Langhorne Clemens (1835–1910), was an American novelist, essayist, journalist, and humorist. His sharp observations of American life animate works such as *The Adventures of Tom Sawyer* and *Adventures of Huckleberry Finn*. The saying “Twenty years from now you will be more disappointed by the things that you did not do than by the ones you did” is widely attributed to Twain, but its provenance is uncertain. No reliable primary source connects it to a particular book, speech, letter, or occasion, so it is best treated as a popular saying rather than a verified Twain quotation.
The line’s appeal lies in its reversal: we often fear making a mistake, yet over time the chances we never took can weigh more heavily than the ones that went badly. That does not mean every risk is wise or every hesitation a failure. Instead, the quote invites us to consider whether caution is protecting something important—or merely keeping us from trying. Its message resonates because it turns regret into a prompt for action: make room for curiosity, meaningful goals, and experiences that matter before they become only possibilities we remember.