Hang around people who are better than you all the time. You do pick up the behavior of people who are around you. It will make you a better person. Marry upward. That is the person who is going to have the biggest effect on you. A relationship like that over the decades will do nothing but good.
A related sentiment is "It's easier to change your friends than it is to change yourself."
Mark added, "And if you can’t find/identify people who are better than you, you’re probably an asshole."
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P.S. - Congrats to Buffett for earning the highest U.S. civilian honor (with coincidentally the lamest-sounding name), "The Medal of Freedom".