Warren Buffett comes across in the media as a very smart man with an impish sense of humor, particularly in his countless appearances on CNBC. But as one of his grandchildren found out, crossing the Oracle of Omaha can lead to a world of hurt.

The world's richest man severed ties with Nicole Buffett after she appeared in the well-regarded documentary "The One Percent," in which the scions of billionaires, including New York Mayor Mike Bloomberg, spoke about what it was like to grow up wealthy. The film, made by Jamie Johnson of the Johnson & Johnson (NYSE: JNJ) family, is well worth viewing.

Ms. Buffett, though, made the fatal error of not informing her grandfather about the motion picture debut, according to Marie Claire: "Asked in the film how he'd react to her interview, Nicole responds, 'I definitely fear judgment. Money is the spoke in my grandfather's wheel of life'."

That was a foolish thing to say and the younger Buffett knows it. The head of Berkshire Hathaway Inc. (NYSE: BRK.A) has argued his whole career that money is not everything. He abhors inherited wealth and has argued persuasively why an inheritance tax is good thing. That explains why he is giving away most of his money to the Bill & Melinda Gates Foundation.