Milton Friedman is the most influential economist of the past half-century and, at the age of 92, is still as sharp as a tack (here are previous posts on Mr. Friedman). Craig Newmark passes along this recent interview of Mr. Friedman, which includes the following pearls of wisdom:
On Social Security:

Asked why, if Social Security is so terrible, it is the most popular government program in American history, Friedman replied, “Well, because why does a Ponzi game work? It’s easy to understand why it’s popular. So far, on the average, retirees have gotten more out of the system than they put into it. ”
What about the fact that Social Security has reduced poverty among the elderly?
“Well,” he replied, “what it has done is transfer a lot of income from the young to the old. It is certainly true it has made the old people of the United States the best treated old people in the world.”
But why is that a bad thing? “Oh,” Friedman replied. “It’s not a bad thing for them, but what about the young?”

On rent controls and his influence in political debates:

When [Mr. Friedman] moved to San Francisco in the 1970s, the city was debating rent control, he recalled. So he wrote a letter to The Chronicle saying, “Anybody who has examined the evidence about the effects of rent control, and still votes for it, is either a knave or a fool.”
What happened? “They immediately passed it,” he laughed.

On a related note, in this post, John Hamilton compiles his favorite Friedman quotes from Mr. Friedman’s famous book, Free to Choose, which includes my favorite:

“[A] private firm that makes a serious blunder may go out of business. A government agency is likely to get a bigger budget.”