In the 1990s, the success of the movies of AKIRA and Ghost in the Shell meant that many in the West professed to be 'into manga', in many cases without ever seeing any more examples of the form than those two films. Or appreciating the difference between manga and anime.
Or that there's a lot of different genres within the anime/manga world, besides dystopian sci-fi. This has created a weird situation where many fans of old-school anime want the industry to go back to "the way it used to be," i.e. focused on dystopian sci-fi; but it never actually was focused on that genre. For some reason, the other types of shows didn't start getting imported until years later.
Happens a lot with movies — movies known for being good, but unseen by many of the people who praise them. Many of these nevertheless become used as benchmarks, which terrible movies will often (according to many a review and rant) be described as "making merely mediocre movies look like...".
A lot of the classic non-American film directors — Bergman, Fellini, Kurosawa, Truffaut, Antonioni, Herzog, De Sica, Godard, Renoir, Tati, Tarkovsky, Bertolucci, Pasolini, Kieślowski, Bunuel, Ozu, etc.
The Wizard of Oz partially averts this. Almost everyone has seen it, but most people only watch it when they're kids or when they're with kids, and so can go many years without being exposed to it. It's common to watch it again after a long absence and being surprised by a sight gag, quip, or sequence that one had totally forgotten about.
The Bible. Some people who espouse it as the direct word of God haven't read more than a few verses of it (as opposed to Biblical scholars, who tend to analyze and discuss it academically). On the flip side, some people who hate it haven't read it either. Some traditions do cover a large portion of the text over the course of a few years, though.
In Islam, it is very important to learn about the Koran. It's not limited to just reading it either. Memorization of Al-Fatiha is important, as it is needed for prayer. Indeed, there are many people all around the world who have memorized the Koran by heart. Like with the Bible, there are many who praise the Koran yet rarely ever read it.
William Shirer characterized Mein Kampf as the bestselling book in Germany between 1934-1944 that was never read by most Germans who bought it.
War and Peace. Said to be one of the great Russian classics, but people tend to shy away from it due to it being a thick Doorstopper of a book.
Hey, any famous Doorstopper is in default danger of this trope or its inverse, especially the "modern" stuff like Pynchon or Joyce.
In the same vein, Gulliver's Travels - also everybody "knows" it...the shorthand, dumbed down version, that is.
Lord of the Rings gets this, too. Mostly for people who haven't exactly read it, but praise it more for what they accomplished.
Nineteen Eighty-Four. Many phrases from the book, like "Big Brother", "thoughtcrime" and "Room 101", have entered pop culture, so quoting these phrases and being aware of the general theme of "totalitarianism and censorship are bad" is probably enough to convince someone else who hasn't read it that you have.
Orwell in general falls into this a lot, particularly from people who have either never read any of his work other than 1984. Anyone describing Orwell as a conservative or a "fanatical anti-Communist" is talking out of their proverbial arses.
Why I Write: Every line of serious work that I have written since 1936 has been written, directly or indirectly, against totalitarianism and for democratic Socialism, as I understand it
Mark Twain would be displeased to learn that The Adventures of Tom Sawyer now meets his definition of "classic." When most people discuss the book, they refer to one scene — Tom tricking his friends into whitewashing a fence for him. This occurs in Chapter 2. Either that is an incredibly awesome scene, or it's got 'most quoted' status in school textbooks, or most people stop reading around page twenty. You can tell that someone has actually read the whole thing when they refer to other memorable scenes, like getting lost in the caves, and Tom and Huck attending their own funeral.
Much like the Tom Sawyer example above, you can tell whether or not anyone has actually read Don Quixote by whether they remember anything about it other than the windmill scene.
Richard Feynman mentioned in his autobiography a case when one publisher sent a schoolbook to the California State Curriculum Commission, but it wasn't ready for print, so it had empty pages. Six out of the ten members of the commission still rated the book favorably — literally judging it by the cover! Ironically, it was one of the highest rated books, and according to Feynman's autobiographical account, none of the other members understood why he hadn't rated the textbook.
Many works of mythology, such as The Epic of Gilgamesh and various other texts of Classical Mythology and other myths. Although many are well-respected as inspirations for modern fantasy and great storylines by themselves, few people have probably actually read them.
Part of the Framing Device for why The Princess Bride (the book, not the movie) is an 'abridged version' is because the author (who is, in the Framing Device, claiming to merely be an editor) recommended this book highly to his son, despite the fact he'd never read it, having only heard the (much shorter) version his father read to him as a child.
While Twilight did have some... questionable... aspects of vampires, amongst the cries of how they ruined vampires like Dracula in Twilight is allegedly that they are moving during the day - which pretty much shows how familiar people actually are with Dracula.
A Brief History of Time and Gödel, Escher, Bach are both well-known for this, the former having been described as "the most unread book ever written". These tend to be the sort of books that people leave on their bookshelves or coffee tables to look sophisticated, but because the books are quite challenging to read, only a handful of people who own them have ever finished them.
Many people who praise the works of H. P. Lovecraft can't name a Lovecraft monster other than Cthulhu, who isn't a major character in his pantheon to begin with.
There are very few people who have seen acclaimed shows like The Wire in full, yet because it is the general opinion of critics, they immediately proclaim them "the greatest TV show ever made" after watching the first few episodes. Which is silly, given that it's a very slow-burning show which takes several episodes to get going.
Quite a few shows on HBO or Showtime have this problem, probably because those are higher tier networks so a lot of people can't see them (legally, anyway) until they come out on DVD, but everybody wants to seem "cultured".
There's an extra on an L Word DVD that shows a work-around: They re-enact the episodes using an AfterEllen.com recap. It makes for some...odd viewing. Presumably, they get the DVDs once they become available.
Though AMC is not on the same tier of network as HBO or Showtime, a lot of shows on it, especially Mad Men and Breaking Bad, are in the same situation as described above. Both shows get raves from seemingly everyone despite only getting ratings in the low millions.
Happens with a lot of very successful and famous rock groups. The Beatles, The Rolling Stones, AC/DC, Pink Floyd, Led Zeppelin and many other older rock groups, in spite of having legit and quite large fanbases, are popular among this group of people, particularly in the case of music debates where one will list these bands and others to prove their musical taste is "superior" to the other person's. An exception to this is when someone uses a Progressive Rock group like Yes. They will often be seen as a music snob by others.
The Ramones are probably a better example. The shirts are more popular than the band ever was. Most people probably don't know that three of them are dead.
Happens in the classical music world as well; everyone's heard of Bach, Mozart, Brahms, and so forth (Beethoven gets a pass for the "Ode to Joy," "Für Elise," and the opening of the Fifth Symphony) but few can name a piece of theirs or identify it on hearing (to Jeremy Paxman's eternal frustration on University Challenge). Made more confusing by the fact that their best-known hits are sometimes not at all similar to the rest of their oeuvre - Brahms' Wiegenleid ("Lullaby"), for example, which is almost entirely unlike everything else he ever wrote.
Michael Jackson gets a lot of accolades, especially since his death, proclaiming that he's "the greatest entertainer of all time!" But — not unlike William Shakespeare (see Theatre below) — while the solo albums Off the Wall, Thriller, and Bad are much-heard and loved, most people only know a handful of Jackson 5 singles and a few Dangerous tracks otherwise. This became a problem for the Cirque du Soleil show Michael Jackson The IMMORTAL World Tour, as both professional critics and casual showgoers were exposed to a lot of the lesser-known Jackson numbers (both solo and with groups) and didn't like what they heard. Also, while his Thriller music videos are hailed as high points for the form, only a few of the many clips that he made afterward come close to matching them.
Due to the negative feedback about the fourth edition of Dungeons & Dragons, many gamers have an utterly unhealthy love of Tabletop Games/Pathfinder as it's an outgrowth of the game's third edition (which, ironically, also had a loudly negative reception and people rushing back to second edition). This coupled up with fourth edition being marketed aggressively towards new players, with Wizards of the Coast supporting game shops to run "Encounter" events to show of 4E, to result in a lot of new gamers praising Pathfinder to death in order to agree with older gamers rather than trying it and seeing if they liked it first.
William Shakespeare is so well known for being "the greatest author in the English language, and possibly any language," that many people will not hesitate to dump heaps of praise over his entire body of work and over all aspects of his writing. While some of his best-known plays are required reading in most high schools, Shakespeare wrote quite a few plays, and not all of them were works of staggering genius. Some plays are preserved only out of a Gotta Catch 'Em All sense of duty to study Shakespeare's entire body of work, rather than for their individual quality. Also, many people don't know that most of Shakespeare's plays were adaptations/rip-offs of previous works. Shakespeare punched up the plot and wrote the dialogue (the latter of which someone would argue is the point of reading Shakespeare), but did not himself invent the stories.
Another thing about Shakespeare is that his works are difficult to read for the average Joe, as in they are written in what can seem like a different language. How many high-school students would pass a test on Shakespeare without an explanation on the words used? This makes anyone who proclaims that Shakespeare is a master of language, but when pressed doesn't even know what half of the dialogue means, particularly amusing.
The works of Menander received loads of acclaim throughout history... despite all of his works existing solely as fragments from the eleventh century to the end of the nineteenth. Since then, a few of his works were recovered (Dyskolos, or The Grouch, has been found in its entirety, and now about three-quarters of The Samian Woman are now known), leading to an inevitable Hype Backlash.
The UK PC Gamer magazine's review of Far Cry 2 was more like a review of the press pack circa six months earlier; features were mentioned that didn't exist, the main factions were repeatedly called by the wrong names, and much was made over the ability to pick factions and missions, something you can't do unless you really hate advancing the plot.
Compare the number of people who have praised Psychonauts or Beyond Good & Evil to the actual sales figures of those games. You'll almost certainly find the former number far exceeds the latter.
Rather hilariously true of many Amazon.com game reviews since 2000 onward, with people giving five star reviews to games that won't come out for months, sometimes reviewing the game based on a couple of screenshots and rambling about features that don't exist (but clearly should and will in five months!). Amazon's gotten better about it, at least.
ICO is widely praised as being a simple yet artistic, touching game. Finding people who actually played it, though, is not quite easy.
Terraria had a community like this pre-release, with many people praising the game well before it came out and claiming it to be nothing like Minecraft, despite only a limited number of them having played it at that point.
Then there are Touhou Project fans that are only familiar with the games through canon and semi-canon gaidenworks by the games' creator (from fantasy-land travelogues up to and including a book-length short story series), and praise the project as a whole because there's no single phrase referring to these works alone.
A good portion of the Dangan Ronpa fandom has not played the games, due to the fact that they currently don't have a proper release in their language or region; a text-heavy game is nearly pointless to play if one is not adept with the language it's in. It does, however, have an English patch, but it requires making modifications to one's PSP to play. However, there is an anime adaptation out, for those who don't want to deal with English patches or a Let's Play.
There are certain fangirls who claim to love games like Kingdom Hearts and will tell you all about their ships, but have never actually played the games.
Even before the MOTHER series earned its status as Sacred Cow, there were many people repeatedly praising EarthBound and talking about how awesome it is. Now look at its sales figures, and ask yourself how many of those people actually played it when you could actually obtain a cartridge for a reasonable price.
Harvest Moon fans are quick to call Harvest Moon 64 the best in the franchise despite the fact few have played it. A good majority of the fanbase got into the games through (More) Friends Of Mineral Town, A Wonderful Life, and the Nintendo DS games plus 64 was obscure as it was; the 64 wasn't as popular as the Playstation and even kids who owned a 64 were more likely to pick Mario than some farming game. They simply hear other fans praising it so they praise it too. It doesn't help that it will likely never be ported onto the Virtual Console.
Homestuck has a number of fans who only ever read the parts of the comic that deal with one of the resident Humanoid Aliens species, the trolls. The troll characters are teenagers who are quirky and easy enough to identify with that it is often unclear when browsing the plethora of fan works whether some people are even aware that there is a story going on with these characters, or whether they simply latched on to the character designs, alien romance habits and exaggerated manners.