Magnum Opus Dissonance

""A book for girls being wanted by a certain publisher, she hastily scribbled a little story describing a few scenes and adventures in the lives of herself and sisters - though boys were more in her line - and with very slight hopes of success sent it out to seek its fortune."

"Things always went by contraries with Jo. Her first book, labored over for years, and launched full of the high hopes and ambitious dreams of youth, floundered on its voyage, though the wreck continued to float long afterward, to the profit of the publisher at least. The hastily written story, sent away with no thought beyond the few dollars it might bring, sailed with a fair wind and a wise pilot at the helm into public favor, and came home heavily laden with an unexpected cargo of gold and glory.""

- Louisa May Alcott's vicarious description of her experience writing Little Women, from Jo's Boys

""You know, it's funny how wrong an artist can be about his own work. The one composition of Tchaikovsky's that he really detested was his 'Nutcracker Suite', which is probably the most popular thing he ever wrote.""

- Deems Taylor, Fantasia

The serious work that you lavish all of your efforts on and have the highest expectations for will not receive nearly as much acclaim or success as the one you just toss out to pay the bills.

What happens when a writer or artist deliberately tries to create their Magnum Opus? They slave over it for years, pouring 110% of their heart and soul and energy and sanity into it, and confidently expect it to be huge, monumental, Genre Busting, and assure them eternal fame and honor... and what is the response? "Meh, it's So Okay It's Average."

But what happens when the same artist just writes or creates something for fun or profit with no big plans, hopes, or expectations for its success? Heck, they know it's not that good but figure it will at least pay the bills this month. They're so busy working on that inevitably earth-shattering magnum opus, they don't even give this other silly little project much thought. Whoever commissioned it is sure to be disappointed, but it's no big deal; the public won't even notice its existence enough to laugh at its pointlessness anyway.

Cue Situational Irony! That book, movie, or painting that the creator couldn't care less about becomes an instant sensation. They're hailed as a genius, worshipped for blessing the world with this wonderful new classic, immortalized in parodies and homages, and earn an eternal place in history for their brilliance and creativity. That masterpiece they had such high hopes for will quickly fade into obscurity, but they will be remembered and celebrated for this little hackwork forever.

How does this happen?

When the effect is somewhat delayed, see Vindicated by History.

Sub-Trope of the Centipede's Dilemma and Sister Trope to Creator Backlash (often a good source thereof, too). Sub-Trope of Murphy's Law. Compare Self-Deprecation, Sweet and Sour Grapes, Springtime for Hitler, and It Will Never Catch On. Also see Consolation Award for when the work that is considered the best by public is not the most awarded.

Comicbooks

 * Peyo's favourite work, and actually his original main one was Johan and Peewit (Johan and Pirlouit in its original French title)... But, one day, in one of this series' album, appeared a certain band of little blue creatures. They were intended to be one-shot characters, but quickly became Ensemble Darkhorses... And from then, The Smurfs (Les Schtroumpfs) became the single most remembered work of Peyo.
 * Spider-Man co-creator Steve Ditko doesn't like to talk about Spider-Man. More precisely, he prefers not to talk about the character and he vowed never to draw the character again after he left Marvel in 1967. He does still occassionally pop up to complain that Stan Lee takes too much credit for Spidey's creation but that's the extent to which he discusses Spidey. Ditko prefers to promote his Ayn Rand inspired comics, which a large majority of readers (who even know of them) find tedious and unreadable.

Fan Fiction

 * The brain breakingly epic Tamers Forever Series was originally intended to be a mere side project while the author overcame his writers block.
 * Cupcakes is an extremely gory My Little Pony Friendship Is Magic fanfic that was written on a whim because the author wanted to see if it would actually get any attention. The result: a fanfic so infamous that reading it is more or less a pre-requisite for understanding many of the in-jokes and references in the Friendship Is Magic fandom. It's spawned an incredible number of spinoff fics, and most recently, one of the show's animators made a rather gruesome music video based on the fic. The chances are very high that Lauren Faust, creator of the show, knows what Cupcakes is. Most bronies might not even know that the author actually wrote more 'normal', more serious works that don't exactly get a ton of attention compared to Cupcakes.
 * MLP: The Games We Play, a 379 page drama, while far from being an unnoticed piece of work, was promptly out-viewed by the author's later fic - a one shot of the philosophical ramblings of Pinkie Pie watching paint dry, something the author wasted little time pointing out in a blog post.
 * The dark fic Pokémon Master by Ace Sanchez became sort of this.

Films -- Live-Action

 * Orson Welles believed that his greatest completed film was either Chimes At Midnight or The Trial, not Citizen Kane.
 * This is something of a recurring narrative in the New Hollywood era of the 1970s, with numerous directors agreeing to do studio pictures in order to get the funding for the more personal pictures that they wanted to make. The studio pictures, which were usually made under some level of studio observation (however minor), would go on to be widely acclaimed as great films, whereas the more personal pictures -- usually made under an atmosphere of Protection From Editors and the director's ego having spiraled completely out of control -- would bomb disastrously.
 * A textbook example: the Western Heavens Gate was the passion project of Michael Cimino, director of the acclaimed Vietnam War movie The Deer Hunter. It's considered one of the biggest bombs in film history, not only ending Cimino's career but also the New Hollywood era.
 * Most of the Monty Python crew (John Cleese in particular) consider Life of Brian to be their greatest work, in part because it has a central theme and tells a complete story, while their other works are more less a series of sketches. While Life of Brian is still very popular with Python fans, many of whom consider it to be the superior film, but Monty Python and The Holy Grail has penetrated pop culture to a far greater degree.
 * Successful director George Lucas put a lot of work into Star Wars, but he always intended to use the money it raised to work on the smaller, more personal projects that had brought him fame, such as American Graffiti and THX 1138 (Film). Billions of dollars later, the smaller, more personal projects did get made (but with different directors). The first was the 1994 box office disaster Radioland Murders and the second was the unsuccessful 2012 film Red Tails.
 * Ask people what Alfred Hitchcock's best movie was, and you'll get different answers. Maybe Psycho, maybe Vertigo, maybe North by Northwest. Most probably won't mention the film Hitchcock regarded as his best, 1943's Shadow of a Doubt.
 * Dennis Hopper's attempt to follow Easy Rider with an ambitious project he was conceiving for a while, The Last Movie, bombed so hard that it prevented Hopper from directing again for nearly a decade.
 * Leo McCarey directed two movies of 1937: the light comedy The Awful Truth and the cynical drama Make Way for Tomorrow. When he received the Best Director award for The Awful Truth, he said that he'd been awarded for the wrong movie.
 * Out of all the actors to play Batman, Val Kilmer has never been very well received. Many loved Michael Keaton and hated George Clooney but were really just indifferent to Kilmer, finding him dull. However Batman creator Bob Kane felt that he played the character best (Granted Kane died before Christian Bale donned the cowl).
 * David Cronenberg's (arguably) two most popular films, The Fly and A History of Violence, were actually born out of Troubled Production on two films - he went into the director's chair on the former after he was fired from production on Total Recall, and in the commentary, says he was "interested in it somewhat" (he didn't write the original script, just some patchwork), and admitted that he didn't like the original 1958 film. The latter film is one which he did primarily for the paycheck after having to defer his salary on the now-forgotten Spider. Unlike many of the creators here, he has come to appreciate these projects, and talks in interviews about doing a potential companion piece to The Fly.
 * Roberto Benigni has stated in several interviews that he wanted to do his version of Pinocchio since he was a child. It was only after the success of Life Is Beautiful that he was given the freedom to pursue this project, which was poorly received outside of Italy.
 * Sucker Punch was a pet project of Zack Snyder that got negative reviews and barely recouped its budget at the box office.

Literature

 * Ender's Game was originally just another short story that Orson Scott Card wrote to pay the bills. He only expanded it into a novel so that it could serve as an introduction to Speaker for the Dead (the story that he really wanted to tell). While Speaker is certainly well-regarded among sci-fi aficionados, Ender's Game has become one of the most widely read sci-fi novels of all time, and it's now required reading in many middle schools.
 * Neuromancer is William Gibson's most famous and acclaimed work because it invented the Cyberpunk genre and featured commentary on the information age decades ahead of its time. But in terms of actual literary merit, Gibson considers it one of his weakest works (keep in mind, it was his first novel). Compared to his later novels, its characterization is minimal and the plot is very straightforward.
 * Little Women for Louisa May Alcott; she made the same thing happen to Jo in its final sequel Jo's Boys.
 * Jane Austen thought Pride and Prejudice, her most popular novel, was "too light and bright and sparkling" and deliberately planned afterwards to write something more serious with a little "shade." The result was Mansfield Park, her least popular novel.
 * Mark Twain's favorite of his works was Personal Recollections of Joan of Arc -- ever heard of it?
 * In 1900, when asked which of his works was his favorite, he answered, "Huckleberry Finn." Twain tended to go back and forth on which of his works he preferred, especially as his mood darkened late in his life; Finn had an odd place with him because, even when he was alive, it was a lightning rod of controversy, amassing an impressive list of libraries it was banned from.
 * Lewis Carroll greatly preferred Sylvie and Bruno to his Alice books.
 * Douglas Adams always considered Last Chance to See his favourite work. While not a non-seller as such, it is much less known than some other books of his.
 * Charles Dickens wrote enough other highly acclaimed and popular books that he only presents a borderline example, but A Christmas Carol follows the mold: he wrote it in a hurry for the money and it continues to be one of the best known and most imitated of his works.
 * Robert Asprin started work on Another Fine Myth for laughs, merely to give himself a break from the grimness of another book he was writing, The Cold Cash War. Nowadays, he is fondly remembered for the Myth Adventures series, while Cold Cash War gathers dust alongside other ur-Cyberpunk dystopian sci-fi.
 * William Shakespeare apparently thought more of The Rape of Lucrece than King Lear. This is largely due to Values Dissonance; at the time, epic poetry was considered the highest form of literary art; plays, on the other hand, were seen as lowest-common-denominator trivialities. Today, of course, his plays are better known than his (still great) poetry.
 * The reverse was true of the 19th-century British Romantic poets. Byron, Keats, Shelley, and their peers were obsessed with reviving English drama, and kept churning out faux-Shakespearean plays that seldom rose above mediocre. In time, many of them thought that this failure pretty much invalidated Romanticism. When worrying over how posterity would judge them, they never seemed to think their lyric poetry could count for much.
 * David Weber is famous for his Honor Harrington books, while his Safehold books are being considered the critically preferred work. But it's The War Gods that's his favorite, and he's described what he's written so far as The Hobbit in that series to the Lord of the Rings, and states that work will be the one that lasts.
 * H.P. Lovecraft considered The Call of Cthulhu to be one of his weaker stories.
 * Much of the Mythos's dedicated fandom actually agrees with that.
 * At different times in their careers, both the poet T. S. Eliot and the author Henry James thought their real destiny lay in writing for the theatre. Unfortunately, James was not a particularly good dramatist, and while Eliot did write some well-known plays (such as Murder in the Cathedral), none have reached the fame of The Waste Land or "Prufrock".
 * Anthony Burgess resents that he's best known for A Clockwork Orange, which he thought shallow compared to his other works.
 * Harlan Ellison expresses his frustration in one of his audiobooks over the fact that "'Repent, Harlequin!' Said the Ticktockman", a story he banged out in a day, is so popular and has been reprinted many, many times; whereas "Grail", a story he slaved over for weeks, revising it several times, and in his opinion one of his best, had never been reprinted.
 * Mario Puzo wrote The Godfather in order to pay his bills, as well as to get attention for his more "literary" novels, which he felt were more representative of his style. 40+ years later, Puzo is the "Mafia author" (hardly anybody remembers he wrote the script for the first Superman movie) and his other literary works are forgotten. Ironically, pretty much everybody involved with the motion picture did so in order to make money to bring their other projects to light.
 * Even worse, the book is typically regarded as only "ok" or "good" - it's really only remembered because of the movie, one of the rare cases of the movie being better than its source material.
 * Ernest Hemingway regarded the critically lambasted Across the River and Into the Trees as his greatest work.
 * J.R.R. Tolkien wrote The Lord of the Rings merely in accordance with popular demand for a sequel to The Hobbit - his true labor of love was The Silmarillion, which he spent essentially his entire adult life writing and which he was still polishing and rewriting when he died. Partially averted in that, despite using it as a backstory for his published novels, he never really intended The Silmarillion to be published - writing it was just a leisure activity for him.
 * Cecil Day-Lewis (Daniel's father) was Poet Laureate in the UK and wrote a lot of serious poetry and verse drama, but he also wrote detective novels to pay the bills. Particularly in the 50s and 60s he was far better known for the detective books (written under the name Nicholas Blake), some of which were adapted for film and TV. His poetry was never the equal of contemporaries like Auden or Larkin, and is now largely forgotten, but his detective novels are still regarded as classics by some.
 * Philip Larkin, meanwhile, wanted to be a novelist rather than a poet. His two novels are read only by a few academics, but his poetry remains popular, acclaimed, and even quoted (even if his most-quoted poem is mainly so because of its Cluster F-Bomb).
 * Charles Perrault published writings and essays about art that have mostly been forgotten centuries later. But the work he is still most famous for, his fairy tales, are still popular today. Ironically enough Perrault felt ashamed about these childish stories and published them under his son's name.
 * Same holds for The Brothers Grimm, who considered their dictionary as their greatest achievment. Said dictionary is even in use today by language scientists, but everybody else remembers them for their Fairy Tales.
 * Thomas Hardy considered Jude the Obscure his favorite and best novel. Critics at the time hated it and Hardy only wrote poetry for the rest of his life.
 * Edgar Rice Burroughs considered John Carter of Mars stories to be his best works. They are rather obscure compared to his other series, Tarzan.
 * Pyotr Pavlovich Yershov wrote dozens of poems, plenty of stories, and considered them to be much better than some fairy-tale poem he wrote in simpleton language when he was young. Except today, the poems and stories are all but forgotten, while The Little Humpbacked Horse earned him a statue for composing a folk tale.
 * John Buchan is most remembered for codifying the Spy Genre with The Thirty-Nine Steps, but the novel he considered his best was the historical romance/fantasy novel, Witch Wood.
 * At The Cavalier Years in Spain, money was found in Theater, and glory was found in Poetry. Miguel de Cervantes wrote a comedy book that didn’t get noticed by the critics. Nonetheless, it was successful enough for the editor kept asking for a Continuation because Money, Dear Boy. But Cervantes had Attention Deficit Creator Disorder and wanted to write a lot of projects that would bring him glory, like “Los trabajos de Persiles y Segismunda”. No one took the comedy book seriously, not even Cervantes. Maybe that continuation would have never seen the light of day if not for a Fan Fiction writer that wrote himself the second part, doing the worst insult you can do to an author: A Fix Fic, because Cervantes wrote some characters deserving of a better writer. Cervantes decided to write the best second part he could, and so we have now Don Quixote.
 * Doctor Arthur Conan Doyle created a detective character based on an old medical professor whose techniques and insight had always impressed him in order to pay the bills while he worked on the historical epics he loved so much and which he was sure would make his name and reputation as a writer and artist. Unfortunately for Conan Doyle, the detective character was Sherlock Holmes, who became one of the most iconic characters of all time, while Doyle's historical dramas, which he much preferred, are largely forgotten. Doyle was not happy about this -- he even tried killing Holmes off at one point, but fan backlash forced him to do an about-face.

Manga

 * Go Nagai created Mazinger Z as a kid-friendly side project while he worked on the (much darker) Devilman manga. Guess which one became the bigger hit? (That didn't stop him from exploiting Mazinger to the hilt, however.) That being said, Devilman was still phenomenally successful in the end, but it still qualifies for the trope.

Music
""It was our best work, my favorite album we’ve done, and the one I’m most proud of.""
 * Many popular artists consider their later output to be their best, while their fans always prefer their earlier stuff.
 * David Bowie's entire career is rife with this, as the songs he wrote for art are not very well known, and the songs he wrote for commerce are huge hits. However, the first and biggest example, for him, would be a little song he slapped together out of boredom... he was actually embarrassed by it. "Space Oddity", his first hit - and still popular to this day.
 * Many Black Sheep Hits.
 * Probably the most infamous example is Warrant's "Cherry Pie," written in about twenty minutes at the request of the producer who didn't think the album they'd recorded had a radio hit. This joke song worked far better than intended, overshadowing their other work to the point that many people think it was actually recorded by Poison.
 * Van Morrison does not consider "Brown-Eyed Girl" to be among his best songs. Most people feel differently, although critics tend to prefer Astral Weeks.
 * Well, he didn't particularly like Astral Weeks either. He wasn't allowed to use the musicians he wanted and was forced by the studio to use a bunch of jazz session musicians, and so gave them no real direction in the studio, letting them jam as they liked because he didn't really care. He got his way starting with Moondance and went on to a largely well-regarded career, but as noted most critics prefer Astral Weeks, the album he ignored as he was making it, made in a style to which he never returned.
 * The Hollies' recording of Graham Nash's big Sgt Pepper-style production, "King Midas in Reverse", made only a small dent on the UK singles charts. Their next single, "Jennifer Eccles", a lightweight pop number they pretty much wrote as a joke, became a huge hit. Nash was not pleased.
 * Gustav Holst's The Planets is the most popular of his works, however the composer did not count it as one of his best.
 * And Holst's favorite movement of The Planets was "Saturn," but it's usually "Mars" or "Jupiter" that are the most popular with audiences.
 * Rivers Cuomo of Weezer has stated that he is embarrassed by Pinkerton, typically considered to be the band's finest moment.
 * Although it wasn't considered the band's finest moment upon release - one imagines if it had received the kind of critical acclaim it currently enjoys upon first release, Cuomo's opinion of it would be rather kinder.
 * Guns N' Roses created "Sweet Child O'Mine" as basically just a song to fill space on the album. It wasn't expected to do particularly well. Now, it is quite possibly their Signature Song.
 * Kurt Cobain of Nirvana didn't think much of "Smells Like Teen Spirit", describing it as "my attempt at writing a Pixies song." In fact, he didn't like Nevermind much as a whole, thinking the whole album sounded much too polished. He always thought that "Drain You" was one of Nirvana's best songs, and couldn't understand why it was never the hit he thought it should have been.
 * Scott Joplin had high hopes for his ragtime opera Treemonisha. It flopped and was forgotten for many decades.
 * Arthur Sullivan would have preferred to be famous for his serious music rather than the comic operas he wrote with W. S. Gilbert.
 * Camille Saint-Saëns did not allow The Carnival of the Animals to be published in his lifetime because he feared it would overshadow his other work (which he considered superior). It didn't work: just try and remember any other pieces by him.
 * The Turtles wanted to move on from their hits to create Sgt. Pepper/Village Green Preservation Society type works, but the record company insisted on more hit singles in the vein of Happy Together. Their response was Elenore, a lightweight pastiche of their earlier works intended as a Take That, which inevitably went on to become a hit. Their later albums, including one produced by Ray Davies, tend to be overlooked.
 * While Sgt Peppers Lonely Hearts Club Band would become renowned as one of the best and most important rock albums ever, the members of The Beatles themselves were divided on the issue; certainly, George Harrison and John Lennon, while not exactly disliking it, later admitted they couldn't see what all the fuss was about. Lennon himself preferred The White Album.
 * During the production of their third album Silver Side Up, Canadian rock band Nickelback (who were previously known for their alternative-rock sound) crafted another album of hard-hitting songs that they believed would finally bring them mainstream success. However, they also cranked out a song in twenty minutes on a lark to fill out the album's running time. That song, "How You Remind Me", became the group's biggest hit, and came to define their musical output since then. It's also been used by critics to show how the band was a musical punchline in the rock world.
 * When The Who were in the process of recording Tommy, Pete Townshend slapped together a Power Pop ballad with no real relation to the story in order to get the attention of New York Times music critic Nik Cohn, who was known to be a fan of certain arcade novelties. That song was "Pinball Wizard", which easily became the most recognizable song off the album.
 * And while Tommy came to be considered the Who's finest work to date, Townshend's aspirations were pegged on its ambitious followup, Lifehouse - which ultimately fell apart due to miscommunication and the Who parting ways with their manager, and stayed dead until Townshend revived it as a solo album and radio play nearly 30 years later, by which time his work was no longer receiving notice on the pop charts. (on the other hand, the album which resulted of the failed Lifehouse sessions, Who's Next, competes with Tommy as the band's Magnum Opus)
 * Lou Reed's followup to the hit album Transformer was Berlin - a Darker and Edgier Concept Album about drug use, depression, abuse and suicide. He considered it his masterpiece. It flopped. He followed that up with the poppy, lightweight Sally Can't Dance which was a hit, and then acknowledged the trope and commented that maybe he shouldn't be on the next album at all. Cue Metal Machine Music...
 * Duke Ellington believed that his Sacred Concerts, which mixed jazz and church music, were the most important thing he ever wrote. Listeners aren't so sure; critics are more likely to cite Duke's collected 1939-1942 recordings, or The Far East Suite, as his greatest work.
 * "Weird Al" Yankovic's album Straight Outta Lynwood was originally going to use the James Blunt parody "You're Pitiful" as its lead single. After Atlantic Records nixed the idea, Al was forced to quickly write and record two new songs to replace it on the album. One of them, "White And Nerdy", is currently his most successful single in the US.
 * While most My Chemical Romance fans consider Three Cheers For Sweet Revenge or The Black Parade their Magnum Opus, vocalist Gerard Way considers their most recent output, Danger Days: True Lives Of The Fabulous Killjoys as this.


 * Sisters Of Mercy front-man, Andrew Eldritch, considers the 90s album Vision Thing to be their best. Most fans agree that their best album was the first, ironically titled First and Last and Always...after making which lead the band to a falling out and lineup overhaul.
 * In many interviews, Pink Floyd guitarist David Gilmour mentions that his favorite Floyd album was neither The Dark Side of the Moon, nor The Wall, but Wish You Were Here.
 * Even though Frank Zappa never named Thing-Fish his masterpiece, he often called it an essential album because of the political message. Yet to this day many Zappa fans revile it as his worst, least imaginative and most unenjoyable record ever! Even the political aspect is so far-fetched that it loses its impact because people are unable to take it seriously.
 * During his 1991 interview with Oprah Winfrey, Michael Jackson claimed he was unhappy after his famous performance of "Billie Jean" during the 1983 Motown special. And solely because he was unable to keep standing on his toes after performing the moon walk for the first time in public. Still many people consider this show to be his crowning performance achievement.
 * Slayer guitarist Kerry King prefers 2001's God Hates Us All over Reign in Blood.

Webcomics

 * Jennie Breeden, author of The Devil's Panties has clearly encountered this trope.
 * Ryan Sohmer made a name for himself with the... divisive Least I Could Do. Then, he decided to do a little side project lovingly spoofing two things he enjoyed: World of Warcraft and Dungeons and Dragons. With a more likeable protagonist, a cool supporting cast, a good Myth Arc, some Growing the Beard and a certain Heroic Comedic Sociopath warlock, Looking for Group grew to vastly eclipse Least I Could Do in popularity and acclaim. Sohmer himself began to eventually view LFG as his magnum opus, as well.

Web Originals

 * Egoraptor claims that his best work is Sequelitis (his web series, not the trope), as compared to Girlchan in Paradise or the Awesome Series, due to both the time and effort he put into the episodes and the fact that he values an ability to make people think over an ability to make people laugh.
 * Not that Sequelitis isn't appreciated; it's just much, much younger (barely a year old) and so far only has three episodes, one of which is only five minutes long.

Western Animation

 * In the early 1990s, Pocahontas was in production at Walt Disney Pictures, and everyone involved was convinced that this would be the great landmark animated feature of the revitalized Disney. By comparison, The Lion King was simply a filler project to tide things over for 1994. Yet The Lion King became the mega-smash hit that would prove to be the pinnacle of Disney's Renaissance and one of their best films in general, while Pocahontas in 1995 became more of a let down that signaled the decline of the company's success.
 * Also occurred with The Black Cauldron (1985) and The Great Mouse Detective (1986). The Black Cauldron was supposed to be the big hit that would revive Disney in the 1980s and The Great Mouse Detective was just a filler film. Unfortunately for The Black Cauldron, management changed at Disney prior to its release and Jeffrey Katzenberg pretty much screwed the movie (claiming it was too dark) and refused to give it any marketing or promotion. As such, at least initially, Black Cauldron flopped (and was all but officially disowned by Disney) while the more traditional Great Mouse Detective was a modest hit at the box office. Despite this, The Black Cauldron managed to become a bona fide cult hit in the following years.
 * Walt himself intended both Sleeping Beauty and Alice in Wonderland to be his joint magnum opus, but neither movie turned a profit during its initial box office release. In the case of Alice, Walt disliked the finished film even before it flopped and regarded it as a mistake for the rest of his life. Sleeping Beauty, at least, has been vindicated by history.
 * During the early 1940s, Disney released the artistically advanced Pinocchio and Fantasia, then the relatively cheap Dumbo. The first two of those movies flopped at the box office (partially because World War II cut off overseas markets), while Dumbo proved profitable enough to keep Walt Disney Animation Studios afloat. Pinocchio and Fantasia later became some of Disney's most acclaimed movies, though.
 * DreamWorks had a similar situation between Prince of Egypt and Shrek. The former was Katzenberg's baby, receiving all of the talent and money, while the latter was the discount animation project, with production shut down several times. (In fact, the term "shreked" became a company term for someone who was sent to work on the film, presumably as punishment.) Prince of Egypt had much critical success and a fairly good box office return (it was the highest grossing non-Disney 2D animated movie until The Simpsons Movie came out, so it's not like the movie did badly), while Shrek is now the company's Cash Cow Franchise and won the first ever Academy Award For Best Animated Feature!
 * It also didn't help that Egypt was focus-grouped to death (naturally, given its potential controversy as a Bible adaptation), whereas Shrek got a lot of stuff past special interest groups and critics because, literally, no one cared.
 * The Thief and the Cobbler was the 30-year labor of love of Richard Williams, better known for Who Framed Roger Rabbit?. Sadly, the copious Executive Meddling that the project received caused him to disown the film, including the highly praised Recobbled Cut.
 * Matt Groening created The Simpsons hastily in the lobby of James L. Brooks' office, where he originally planned to pitch Life in Hell (at the time his most notable work, which had been running for around 10 years in newspapers) as a shorts series. He chose not to because he wanted to keep the rights to Life In Hell. Now few people know Life In Hell, and The Simpsons is considered his Magnum Opus.
 * Groening once made a list of his favorite Simpsons episodes, and choose mostly examples from the first and eighth season, while many fans consider the third to seventh season to be the show's Golden Age. The first season is even generally disliked by many viewers because the show was still searching for its form in those days. Many episodes from the first season are too slow, not particularly funny and even uncharacteristic.
 * Family Guy has an In-Universe example with Brian Griffin. His labor-of-love novel, Faster than the Speed of Love, becomes a massive bomb due to its being an incredibly trite Cliché Storm that unintentionally rips off the Iron Eagle series. After he trashes schlocky self-help books and says anyone could make one, Stewie challenges him to do so, so he throws together Wish It, Want It, Do It, which becomes a smash hit.

Other

 * Isaac Newton is undoubtedly one of the greatest scientists who ever lived, and made multiple groundbreaking contributions to several scientific fields. His Philosophiæ Naturalis Principia Mathematica, which laid the foundation of classical mechanics is considered one of, if not the most important scientific work of all time. Yet the latter was only published due to the insistence of Edmond Halley: Newton considered his most important work to be his studies in occultism and esoterism, which comprised about two thirds of his work.
 * And in his own lifetime, Newton was best known for his work at the Royal Mint, which is why the design of his tomb in Westminster Abbey incorporates many references to coinage and currency, but none to science.
 * Photographer Eddie Adams was best known for his Pulitzer prize-winning photograph of a Vietnamese general about to execute a Viet Cong prisoner, which became an icon of the Vietanam protest movement. Adams later regretted the photograph's notoriety, particularly the demonizing of the Vietnamese forces and the specific general depicted, wishing instead to be remembered for a series of later pictures depicting Vietnamese refugees to Thailand. Needless to say, they are nowhere near as famous.
 * Being President of the United States ranked so low on Thomas Jefferson's personal list of life achievements that it wasn't included in his self-written gravestone epitaph.
 * An episode of QI brought up C.B. Fry, an ancestor of Stephen Fry's and a successful turn of the century British sportsman. He represented England in football and cricket, claimed the world long-jump record in 1913, and reportedly was offered -- and refused -- the throne of Albania following World War One. He could also jump onto a mantlepiece backwards without losing his balance. Guess which one, much to Stephen Fry's irritation, was the only thing that anyone on the panel for that episode wanted to talk about?
 * Most marks would claim Mick Foley's best match to be his 1998 Hell-In-The-Cell against The Undertaker. However, the man himself would vouch for either his 1996 match against Shawn Michaels or his 2004 bout with Randy Orton.