Phoebe couldn't live down her behaviour in Seasons 5 and 6 - her horrible treatment of Cole, misuse of powers and shameless Fanservice. This is in spite of her actually getting punished towards the end of Season 6 for this (the other sisters got away consequence-free with the same amount of personal gain as her) and her wardrobe eventually getting toned down. Not to mention she Took a Level in Kindness by Season 8.
Fans seem to never fail to bring up that Phoebe once strongly opposed Piper's idea of moving out of the Manor after her marriage to Leo, but then proceeded to move out herself one season later after her own marriage to Cole, as if that's the apex of Phoebe's hypocrisy. Never mind that the circumstances were completely different: by the point Phoebe moved out, there were two married couples plus one sister living in the Manor, they now had two people capable of orbing and, most importantly, they believed they had vanquished The Source of All Evil and absolved their Charmed destiny.
That time Piper almost caused a little girl to get hurt by deliberately ignoring her witch duties because she was on a "strike" to get Leo back from the Elders. It’s particularly notable because it happened early in Season 3, when the Charmed Ones were still all about saving innocents, and because none of the other sisters ever flat-out refused to help an innocent in need unless they were somehowcursed (and that includes even Phoebe at her lowest, as the literal Queen of the Underworld!). Piper did eventually come around and was clearly distraught by the consequences of her selfishness, and convinced the little girl not to run away from her problems like she did. This, combined with her realizing that there were valid reasons for why Witch/Whitelighter romances were forbidden helped convince the Elders to release Leo and give them a chance to prove they could make it work. However, in later seasons, Piper acts far more like a brat who just can't get over how the Elders are ruining their lives, all lessons from this episode forgotten.
There's also the infamous sequence in "Hyde School Reunion", where Phoebe and Paige allow a human to be killed by demons. It's often forgotten that the man was a wanted criminal who escaped thanks to Phoebe being under the influence of a spell, and he endangered many other people's lives, with it only being sheer luck that stopped him from killing anyone. He was also threatening their lives at this point too. So while it was a human death that could have been avoided, he wasn't exactly an innocent.
The sisters themselves becoming more selfish. What's often ignored is that this very thing is examined in the final two seasons - where they jump head-first into creating a Utopia with the Avatars and then realise the consequences that come with such a thing. There's also a Season 8 episode where Leo advises Piper to simply avoid hunting demons while they're in disguise, but she outright says she can't ignore it when it's happening in front of her. What's more is that this is the main reason for Billie's Face–Heel Turn towards the end and it's presented as Villain Has a Point. And the finale ensures that the sisters kept fighting demons for the rest of their lives, finding a balance with personal lives and training their children to be able to take over.
Wyatt taking over the show in Season 6. Even though his presence was massively toned down already in Season 7, and Season 8 only gave him a couple of focus episodes and few scenes in-between, he was so overexposed in Season 6, with all the major storylines revolving around him while most of the other characters were written poorly and had rather silly side-plots, that many fans remember the last few seasons as completely dominated by him, some sarkily foregoing the traditional "Prue Seasons" and "Paige Seasons" division for the "Sisters Seasons" and "Wyatt Seasons" instead.
Paige can't seem to live down her arc in Season 6 involving going to various temp jobs. The detractors paint her as an idiot for 'forgetting' about her past a social worker; when the reason she left that job in the first place was because she couldn't balance it with witch obligations, and the temp jobs were an attempt to reconnect with the non-magical world in a new way. And she keeps going to the different jobs because she finds a new problem that requires her help.
Kyle Brody darting Paige with tranquilliser and holding Phoebe at gunpoint to get to the Avatars is one of the most shocking scenes in the show's whole run, especially as he then proceedes to try and kill Leo. Despite time rewinding so none of that ever truly happened and main timeline's Kyle being more reasonable, many fans saw that as the moment when he showed his true colours and could never warm up to him again. The show goes to great lengths to give him a Freudian Excuse that the Avatars had killed his parents (or so he thought), present him as Properly Paranoid and his mistrust of Utopia as a Cassandra Truth, even going as far as having the Elders turn him into a Whitelighter to put the emphasis on the well intentioned part of extremist, but a big part of the fandom has remained adamant that Freudian Excuse Is No Excuse and still hates him with a passion to this day.
Whenever one of the sisters is hostile to and mistrustful of another's new love interest, but then proceeds to / has just recovered from falling head over heels for her own next beau, fingers get pointed in all directions by the fans recalling events from ten seasons ago when X ruined Y and Z's ship but then purused her own with K. Granted, the circumstances are different each time, but the show does a very poor job at keeping the Aesop consistent on whether it's right to trust the currently besotted sister's guts and give the guy the benefit of the doubt, or the other two sistrs are right and the third should listen to her family who knows better. It also doesn't help that all four sisters' judgement gets severely impaired whenever they're falling for someone, so they get Aesop Amnesia whichever version we're choosing to subscribe to this week and they all come across as hypocritical rather than talking from a place of experience due to their own latest disappointment.
The Magical Community was a controversial addition to begin with, and they lost any goodwill from the fans when they turned on the Charmed Ones and sided with Billie and Christy after all the times the Sister had saved their asses. What made them come off as especially entitled and bratty was their falling for a transparent manipulation and not believing that the Charmed Ones couldn’t help them that one time because they got hexed, despite all the magical creatures being, well, magical and familiar with that kind of things. Hardly anyone in the fandom ever forgave them.
The show itself is often remembered for the Fanservice because the network emphasised it (to the showrunners' annoyance). For example "The Bare Witch Project" was hyped around Phoebe dressing up as Lady Godiva - when in the episode she only does it in a brief sequence at the end. The Fanservice was only that heavy in Season 5 and 6, and even so the show was far more straight laced than people remember.
The amount of times the sisters have cheated death is sometimes mocked, even though the circumstances are usually more nuanced; most of the instances involved time travel or else the sisters only being legally dead but getting revived just in time.
The continuity mistakes in Season 6 are especially glaring (although there were a couple in the other seasons too); to the point that Charmed was touted as legendary for its bad continuity. There are in fact several Continuity Nods throughout the series, and Seasons 7 and 8 have lots of Call Backs and references to events and characters from as far back as the first season. Even so, the episode "Witchstock" is not the Continuity Snarl it's made out to be.note It's set in 1967 and features a drastically younger Penny, played by a different actress only eight years before "That 70s Episodes". In fact, the official family tree lists Penny's birth year as 1930, meaning that she is 37 in "Witchstock", and the actress playing her was close to that age. Patty is said to be sleeping over with Alan's sister, meaning a lot of fans assumed she was intended to be a child and therefore wreaking more havoc with continuity. Patty's birth year is 1950, meaning she's either 16 or 17 in the flashback and it's perfectly plausible for a teenager to sleep over with a relative.
Brad Kern couldn't live down not having a picture of Prue in the series finale. He regrets it to this day, claiming it was over budget concerns; the $8000 cost a picture of Shannen Doherty would have required would have meant not being able to bring back one of the other returning cast members.
