These are all at least a little bit dated, but the usefulness has hardly been diminished. They’re all worth reading at least once a year (the last one is worth reading at least every month…)

The days are long, but the decades are short. (By Sam Altman, 2015)

Commencement address to Cal Tech (Richard Feynman, 1974)

The day you became a better writer (Scott Adams, 2007)