In a country where getting and having more seems so normal, people who choose to live with a lot less so they can help others seem, to put it mildly, less than sane.
Zell Kravinsky is one of those people. Kravinsky got rich in the real estate business, and then gave away just about all of his fortune -- $45 million -- to charity. "A lot of people seem to feel I'm crazy," he said.
But Kravinsky doesn't think his extraordinary generosity is very remarkable. "When people tell me that I'm bizarre because of what I've given away, or admirable because of what I've given away, all of those perceptions spring from the same misconception that a $100 [check] to the United Way is all that's required from us," he said.
Karen Pittelman also gave away her fortune to help others. She created the Chahara Foundation to help low-income women and girls with her $3 million trust fund.
At first, she said, it was difficult for her family to understand her decision. "It was hard for them because they put that money aside for my security. They did out of love, and so I think it was hard for them to understand why I wouldn't want it," she said.
Pittelman's explanation was surprisingly simple: "I didn't need that much," she told "20/20."
"I would never judge or say how much any one person needs. But I knew for myself, in my life, that I didn't need this $3 million," she said.
So, she gave her money to groups that help low-income workers and the disenfranchised, particularly women.
"I don't have children now, but if I do I would hope that they would understand if I said to them that I wanted them to live in a world that's more safe, that's more peaceful and that's more just. And so this is my way of trying to do that," she said.
In addition to setting up the Chahara Foundation, Pittelman is also advising others how to make the most of their good fortune by helping others in her book, "Classified: How to Stop Hiding Your Privilege and Use It for Social Change!"
Richard Semmler shares Pittelman's feeling that he doesn't need a lot to live well. For three decades, Semmler has been donating over half of his annual salary to support his favorite charities.
"The total gift giving is at about $770,000 and it may be close to $800,000 by the end of this year," Semmler said.
His goal is to give away $1 million in his lifetime. A college professor who teaches algebra and calculus, Semmler has no trouble doing the math on how that commitment to charitable giving affects his lifestyle.
"There are a few personal sacrifices. It means a fairly small apartment. I am driving a fairly old car. That's a choice I have made. The choice not to have a large house. The choice not to have a pool. The choice not to have a boat on the Potomac River. The choice not to have a new car every two or three years. This way, I can use 55 [percent] to 60 percent of my income to support the charities," he said.
Semmler gives his time as well as his money to charity, serving meals once a week at the Central Union Mission and helping to build houses for Habitat for Humanity.
Kathleen McCarthy, director of the Center on Philanthropy and Civil Society at the City University of New York, is one of many academics who study the relationship between doing good and feeling good.