Creating a daily cartoon can be challenging and a few of the greatest cartoonists have developed burnout. Because of this challenge, some famous cartoonists have ceased creating cartoons to the chagrin of fans.
Calvin & Hobbs
Bill Watterson was the creator of Calvin and Hobbs. His cartoons were among the best in the world. He retired on January 1, 1996. He began Calvin and Hobbs in 1985 and it followed the adventures of a boy named Calvin and his stuffed tiger named Hobbs who came to life when alone with Calvin.
Bill implied that part of the reason for its demise was the constraints placed on him by the publisher. Said Watterson, "I will be stopping Calvin and Hobbes... This was not a recent or an easy decision, and I leave with some sadness. My interests have shifted, however, and I believe I've done what I can do within the constraints of daily deadlines and small panels. I am eager to work at a more thoughtful pace, with fewer artistic compromises. I have not yet decided on future projects, but my relationship with Universal Press Syndicate will continue."
As with most brilliant cartoonists, he refuses to conduct interviews and shuns the public. You can still see his cartoons on GoComics. If you still need more, you can get every C & H cartoon he ever made by buying The Complete Calvin and Hobbes set of books.
Cartoonist Gary Larson
The Far Side
Another great cartoon to bite the dust was the Far Side. Artist Gary Larson began the strip on January 1, 1980 and retired it on January 1, 1995. The primary characters of the one-panel cartoon are cows. At its heyday, it was carried by more than 1900 daily newspapers and translated into 17 languages. Several of his strips were controversial and in one case, he was confronted with legal threats from lawyers.
According to Gary, he made so much money, he decided to retire. He says he will never pick up a drawing pencil again. When asked why, he said that the people who go back to work after winning the lottery are crazy. "Life is Good," he said.  Since his retirement he has shunned the public and refuses to have his picture taken and will not appear on TV.
You can buy every single Far Side cartoon by buying the The Complete Far Side. We would put up a sample strip for you to see, but Gary has appealed to people not to post his strips online. If you want to see one, you can go to his website.
The Boondocks, copyright Universal Press Syndicate
Aaron McGruder was the next casualty. Aaron, an African American artist, created The Boondocks cartoon strip in 1996 for a college newspaper. His strip was frequently controversial with many newspapers censoring strips. McGruder announced that on March 27, 2006, the strip would go on a six-month hiatus. The strip never returned.
Much of the reason for that decision no doubt was his signing a contract with Fox to produce an animated series. Currently the cartoon is on Adult Swim on the Cartoon Network. It's a great arrangement because other artists do the animation and Aaron just signs off on it before it is distributed.
One of the reasons for the strip's demise may have been solitude. Says Aaron, "I spent five years working alone and became a very antisocial and unfriendly person. That’s just how I’m used to working, so there are always unfortunate people who now have to put up with the insanity that up until now has only been inflicted on me. I’m just not good with others. I don’t work well with others. I’m not nice."  Now, many coworkers have to put up with his antics.
For Better or For Worse, property of Entercom Canada Inc.
For Better or For Worse
Lynn Johnston, a Canadian cartoonist, created her final strip on August 31, 2008. She concluded her story the previous day during the weekday strip. Her strip, For Better or For Worse was done in real time. That is, the characters grew up as time went on. Much of what went into the strip was from her own life and family. At its peak, it appeared in over 2,000 papers in 20 different countries worldwide in 8 languages. Although it is in reruns, she will occasionally incorporate newly drawn strips. She also allows other artists to take part in the inking, coloring and lettering. This is a shrewd way to retire. Her strip can go on making her money while she works at her leisure. Originally she intended to retire in the fall of 2007, but marriage problems encouraged her to continue with a new focus on the next generation of children. You can find her website still online.
Opus, copyright Berekely Breathed
The latest casualty is Opus by Berkeley Breathed. The last strip for Opus was on election day, November 2, 2008. There has been no formal announcement about its demise and it caught many of his fans off-guard. Some hypothesize that because his contract ends on January 1, the strip is meant to encourage a more lucrative contract. However, in a Hero Complex article he says he quit because he is "destroying the village to save it." Apparently he was very disturbed by the state of politics at the time. He says in that article, "The best way I can help is to leave politics permanently and write funny stories for America’s kids. I call on John McCain to join me.” 
His strip began as Bloom County on December 8, 1980 and was retired in 1989. He said, "A good comic strip is no more eternal than a ripe melon..."  He then put out the Sunday-only cartoon called Outland that had some of the same characters. That too met its death in 1995. He took an eight year vacation and began Opus, another Sunday-only cartoon. Berkeley created a stir with two of his cartoons that were banned from many U.S.A. newspapers (See them here and here). Although he hasn't come out with a complete set yet, you can get a book of Opus cartoons. Like Gary Larson, Berkeley shuns publicity. You can still see his website online.
All of these brilliant artists received numerous awards including the Reuben Award, Harvey Award, and Sproing Award. As they say, all good things must come to an end. I just wish it wouldn't end so soon.