1. Scrappy-Doo, Scooby-Doo And Scrappy-Doo
Every popular TV show has its beloved and its not-so-loved characters, but it takes a particularly hated character to pass the test of time, and to keep the venom alive after the actual show is dead. Presumably no one was rooting for Ethan on Lost, and Al Swearengen on Deadwood is hard to like, but will anyone remember them a decade from now with the loathing still accorded to the likes of Scrappy-Doo, Scooby-Doo's squeaky, belligerent, know-it-all nephew? There are several ways to draw fan hatred, and Scrappy managed most of them: He was a latecomer to an established and well-liked series, but he completely took over, changing its dynamic and humor; he was a loudmouthed prima donna; he was the archetypal precocious-kid character who always saved the day; and he was a completely unnecessary "update" to the show. Scooby-Doo fans despised him so thoroughly that he became the villain of the nostalgia-courting 2002 live-action Scooby-Doo movie. "Puppy power" indeed.
2. Oliver Martin, The Brady Bunch
Ask any Brady Bunch fan when the series jumped the shark—or ask anybody over 30 to name the worst TV character of all time—and chances are excellent that "Cousin Oliver" will come up. In its last season, amid fears that li'l Bobby and Cindy just weren't cute enough any more, The Brady Bunch tried to bolster its ratings by adding a cloyingly cute moppet to its overcrowded titular family. The show was already on its way out, so Oliver didn't really kill it, but the sloppy desperation of his introduction made sure it went out with an embarrassing fizzle instead of a bang. He also sparked a humiliating trend: Check out Wikipedia's lengthy list of similarly desperate shows with "Cousin Oliver Syndrome."
3. Dawn Summers, Buffy The Vampire Slayer
When Buffy Summers' "little sister" suddenly appeared out of nowhere in the show's fifth season, furious fans screamed their heads off, assuming Cousin Oliver Syndrome had kicked in. Turned out the writers were pulling something clever and self-aware, and there was a plot reason that no one had ever seen or mentioned Buffy's sister before. But that didn't stop her from being an intolerably shrill, whiny, manipulative, troublemaking little McGuffin for most of the rest of the series.
4. Livia Soprano, The Sopranos
Tony Soprano's mother is one of the few characters on this list who was genuinely and clearly designed to be hated. Still, she was probably meant to be hated more as a villain and less as a gratingly intolerable drag on the series. Her poisonous influence on Tony's life and her general inhumanity in the series' first season were so hyperbolic that they were almost funny, but watching such a hateful, ungiving, determinedly miserable bitch do her thing got old fast.
5. Barney, Barney & Friends
Barney was hated by an entirely different group of people than the kids who actually watched his show. Most much-loathed characters earn fans' ire by warping a series' dynamic, hogging screen time in unenjoyable ways, or otherwise detracting from whatever made their show popular. Barney, on the other hand, earned near-universal loathing by escaping his own program and turning up all over the media for a few years, becoming almost inescapable. Well, and also by being insipid, one-note, and incredibly annoying.
6. Steve Urkel, Family Matters
7. Pikachu, Pokémon
Ditto again. It might actually be a toss-up as to which of these three characters had the most irritating voice, or spent the most time pimping their program and its ancillary products.
8. Pat, Saturday Night Live
And speaking of insipid, one-note, and annoying Saturday Night Live specializes in spawning irritating characters, and with its own special form of tenacity, it's insisted on bringing some of them back time after time, even when they begin with dumb premises that don't even sustain their original eight-minute skits. Julia Sweeney as the pudgy, squealing androgyne Pat is one of the worst examples. At least "Massive Head-Wound Harry" never got his own feature film.
9. Ross Gellar, Friends
Which is worse? The serial marriages, the high-maintenance factor, the "We were on a break!" excuse for cheating on Rachel, the self-absorbed indecisiveness, the overall jerkiness? Or the fact that Ross is a David Schwimmer character, played in that hangdog, pity-me-or-I'll-whine-more-aggressively David Schwimmer kind of way?
10. Brenda Walsh, Beverly Hills 90210
Similarly, did fans hate Brenda so much because they hated actress Shannen Doherty—who was frequently rumored to be just as bitchy, troubled, spoiled, and aggressive as her 90210 character—or did they hate her so much because they hated her character?
11. James Hurley, Twin Peaks
At its best, David Lynch's Twin Peaks was a terrific show, full of ominous, oppressive dread and nearly surreal levels of character quirk. At its worst, it centered on weak James Dean rip-off James Hurley pouting, angsting, cruising around on his motorcycle, waltzing into weakly conceived noir side-plots, cutting a mopey demo track, and generally dragging the plot to a whimpering halt. Worse, he tilted the whole show over from "just barely self-conscious about its arty style" into "glaringly, awkwardly conscious of its arty style."
12. Coy and Vance, The Dukes Of Hazzard
Ah, scab characters. They get their own special category of fan hatred. They don't even have to be repugnant in their own right—they just have to step in as inadequate or generic replacements for characters that the fans actually enjoyed. Coy and Vance were harmlessly bland look-alikes who replaced Dukes Of Hazzard regulars Bo and Luke Duke during a fifth-season salary dispute; once the contract issues were ironed out, Coy and Vance magically disappeared. What didn't disappear was viewer disgust over the entire awkward swap. See also such most-hated also-rans as Barney Fife's short-lived replacement "Warren" on The Andy Griffith Show, Mrs. Garrett's longer-lived replacement headmistress on The Facts Of Life, Mulder and Scully's replacement agents Doggett and Reyes on The X-Files, etc.
13. Wesley Crusher, Star Trek: The Next Generation
Pretty much the epitome of the obnoxious precocious-kid character, Wesley Crusher stumbled into a prominent crew position early in Star Trek: The Next Generation, and then spent the next four years generally knowing more than anyone else about everything, and frequently saving the day at the last minute. By the time he left the show, he was well on his way toward godhood, having transcended time and space, at least according to the alien who ran off with him. Fortunately, the actor playing him somehow managed to ascend from universally derided butt of fan jokes to universally loved Internet presence and occasional A.V. Club contributor. Apparently even the worst characters sometimes get happy endings.