Pope Benedict XVI, Sarah Palin, Roberto Duran and other big-name quitters who walked away for better or worse

Pope Benedict XVI celebrates a Mass for priests and nuns in St. Peter's Basilica at the Vatican on Feb. 2.

Pope Benedict XVI shocked the world recently when he announced that he was resigning due to age and health problems. Some people said popes aren't allowed to retire. Some praised him for admitting he was not able to continue and making room for someone else.

Quitting is controversial. Being a quitter is not something much admired. Unless you quit smoking. Some people quit for love, others for money. Some people are forced to quit while others quit on their own. Some can't stop quitting because it gets them attention -- for a while.

Sometimes knowing when to quit is the smartest move a person can make. But it seems that few in the limelight have that wisdom. Check out some of these folks from various walks of life:

Politics / Sarah Palin: After the failed presidential campaign run with John McCain in 2008, Palin resigned as governor of Alaska. She had bigger fish to fry and money to make as a conservative author, pundit and commentator. Running for office is for suckers, it seems. Having run seems the way to go.

Sports / Roberto Duran: In November 1980, Duran had a rematch with Sugar Ray Leonard, from whom he had won a 15-round decision in June of that year. Leonard danced around Duran and frustrated him with fancy moves and taunts. In the eighth round -- and behind on all score cards -- Duran returned to his corner, saying "No mas, no mas [no more]." "Hands of Stone" Duran shocked the boxing world with his lack of heart.

History / King Edward VIII: Edward was king of England, but he threw it all away for the woman he loved, an American divorcee nam! ed Wallis Simpson. It all sounded so romantic, to hear my grandmother tell it. Did you see "The King's Speech?" Edward comes off as a dim party boy and Simpson as a conniving floozy.

Sports / Jim Brown: In 1966, the Browns' star running back was filming the second project of his movie career, "The Dirty Dozen," in London. When delays in filming meant he would miss some training camp at Hiram College, Browns owner Art Modell threatened to fine him $1,500 for every week he missed. So Brown retired.

Games / Bobby Fischer: The chess prodigy who started the game at 13 and who is considered by many the greatest player of all time walked away from a match in 1975 (he declined to defend his title) and didn't play competitively again until 1992.

Music / Cat Stevens: The British folk and pop star recorded platinum-selling albums in the early 1970s only to turn his back on stardom by converting to Islam in 1977. He changed his name to Yusuf Islam and dedicated his life to philanthropic work.

Acting / Grace Kelly: The beautiful, talented Oscar-winning actress quit show business at age 26 in 1956 to marry Prince Rainier III of Monaco. Maybe it's better to be real royalty than Hollywood royalty.

Politics / Richard Nixon: The Watergate scandal eventually led to the resignation of President Richard Nixon on Aug. 9, 1974. It's the only resignation of a U.S. president. Watergate also resulted in prison time for dozens of Nixon's top people. It's not the crime, it's the cover-up.

Sports / Brett Favre: He is the only quarterback in the NFL to throw for more than 70,000 yards, and more than 500 touchdowns, 300 interceptions, 6,000 completions and 10,000 passes. But at the end of his career, he became a serial quitter, hemming and hawing about retiring and not retiring. He made comebacks with the Packers, Jets and Vikings before finally calling his career over on Dec. 10, 2010, following a! concussi! on. Still waiting for one more comeback.

Music / Jean Sibelius: A Finnish composer, Sibelius wrote prolifically until the mid-1920s. But after finishing his Seventh Symphony, he produced nothing of great note for the remaining 30 years of his life. The Finnish composer was all but finished.

Acting / David Caruso: Caruso's first major role was in 1993 on the series "NYPD Blue." Everybody said he was the guy to watch. He shocked the showbiz world by leaving the highly rated program only four episodes into the second season because he couldn't get the bump in pay he wanted. He tanked in a couple of feature films before his career was saved by "CSI: Miami."

Music / Bill Wyman: The bassist announced his retirement from the Rolling Stones in 1993 after a tour. He later played with his own band, the Rhythm Kings.