Benjamin Franklin spent a great deal of time on himself. He made a calendar and put on it certain attitudes he wanted to gain: patience, silence, humility, etc. He identified thirteen virtues and he worked on one per week. By the end of the year, he had repeated all thirteen four times. Sensible people, including non-Jews, work on themselves, and thereby gain prudence and insight. But a Jew stands to gain much more if he lives by the Torah attitudes, by a career of Torah-thought. When a man gains these attitudes, he has put into himself the happiness of the World to Come, because the happiness of the World to Come is the thoughts he takes with him.
Astor, Yaakov. Rav Avigdor Miller on Olam Haba (p. 82). The Judaica Press, Inc.. Kindle Edition.