* {{Adorkable}}: Alan, especially in earlier seasons. While still "mourning" over his divorce, he often gets excited if something interesting happens.
* AlternativeCharacterInterpretation:
** Is Alan's ButtMonkey treatment uncalled for? Or is it LaserGuidedKarma for some unnamed act--or acts--of wrongdoing on his part before the show started?
** Is Charlie just a bastard with a disregard with everything that isn't connected to himself and abusive to Alan for no reason? Or is he jealous of Alan because he was their mother's favorite when they were kids and acting out his unresolved frustrations?
** Is Judith just a complete bitch [[JerkWithAHeartofJerk for no reason]], or is she lashing out after having actually been treated like crap by Alan and Charlie during her marriage to the former?
** Did Evelyn merely insult and emotionally abuse Charlie and Alan growing up, or did she [[ParentalIncest sexually abuse]] them as well? Is this the reason why they both hate women and treat every woman like a substitute Evelyn with whom they still wish to resolve their conflict?
** Due to the actress, Jennifer Taylor, popping up several brief times in earlier episodes before she landed the Chelsea role, some like to play around with the idea that Chelsea's been stalking Charlie since season one.
* BaseBreakingCharacter: Each of the lead male characters.
** You either love Charlie for [[EscapistCharacter having a life that one could only dream of]], while still having character depth by [[JerkWithAHeartOfGold showing genuine affection towards the people he holds close]], or you hate him for being a hedonistic asshole with little redeeming qualities.
** Alan has his fans who [[TheWoobie feel sorry for all the crap he goes through]], even when he brought it upon himself, while others hate him for being [[{{Wangst}} a whiny wimp]] and living rent-free in his brother's (and later Walden's) house with no desire to leave. [[spoiler: However, he does decide to move out of the beach house for good in the show’s penultimate episode, much to Walden’s dismay, but promises to visit often.]]
** Jake, generally, people are divided if he was funnier and more likeable back when he was young, or if he had more of a spine as a teen.
** Walden is generally seen as a ReplacementScrappy for [[TheyChangedItNowItSucks changing the dynamic of the show drastically]]. However, he did [[RescuedFromTheScrappyHeap have some fans]] [[VindicatedByHistory by the end of the series]], generally those who didn't like Charlie to begin with and saw Walden's [[NiceGuy nice]] [[UnclePennybags philantropist]] characterization as a massive improvement.
* BigLippedAlligatorMoment: The SuddenMusicalEnding of "Grab A Feather And Get In Line."
* BrokenBase:
** The show's quality after Creator/CharlieSheen was fired. Most fans seem to agree that Season 9 (the first with Creator/AshtonKutcher) is the show's worst season, as the writers were trying to find their feet again. Some regard the following seasons as an improvement, thanks to a major ReTool in the cast and humor, while others regard them as being only slightly better than Season 9, and still way worse than the first eight seasons.
** The series finale, hoo boy. Either you thought it was a great meta episode with some nice fourth wall jokes, or you hated it because of the constant Charlie Sheen bashing, and you feel Creator/ChuckLorre needs to learn to ''just let things go.'' Or, you could be somewhere in the middle.
* CharacterShilling: Walden can't be in an episode without someone commenting on how damn pretty he is.
* CreatorsPet:
** Rose. Since her first appearance, she's had little depth than being Charlie's obsessive stalker and has never grown past that, but for some reason the writers continue to bring Rose back year after year and had the other characters claiming she was perfect for Charlie. Hell, by the end of season 8, she'd successfully manipulated Charlie over time into thinking she ''was'' the perfect woman for him, even though he had more reasons to think the opposite. Then she passed the MoralEventHorizon by killing Charlie, and not only does Rose [[KarmaHoudini get away with the murder]], but a year later [[spoiler:turns out to have started stalking Walden]]. And unlike Charlie, where she started stalking him because she couldn't let go of a one night stand, was doing so ''for no reason whatsoever''.
** Apparently, she never killed him. She only said she did so no one would [[spoiler:search her house, since she's a good candidate for causing Charlie to go missing for a long time and had been revealed to have been keeping him in a deep hole in her basement, Hannibal Lector-style after he cheated on her while they were in Paris]].
** Walden. The writers loved bringing up how pretty he was every episode.
* DesignatedHero: Charlie and Alan can flip-flop to this because there's so much [[JerkAss douchebaggery between them.]]
* DesignatedVillain: Charlie sometimes gets hit with this whenever he and Alan are fighting. The best example is "All Our Leather Gear is in the Guest Room", Charlie may have been petty about it, but he has every right to not want bowls in his living room that he doesn't like. Instead, the show makes it seem like Charlie's in the wrong and he's forced to take back Alan.
* EnsembleDarkhorse:
** Berta is the ''one'' character on the show who almost ''everybody'' likes.
** Russell the pharmacist.
** Missi, due to being played by Music/MileyCyrus. Both of her episodes have been the season high for season 10.
** Jenny, who was promoted to regular after one episode.
* FairForItsDay: Early episode "An Old Flame with a New Wick" has one of Charlie's exes coming out as a transgender man, and contains all the insensitive jokes one would expect of an early 2000s show dealing with transgender people. However, despite the initial shock, Charlie is rather quick to accept Bill for who he is and helps him adjust to his new life, which was quite progressive for its time. Similarly, the typically caustic Evelyn is in no way put off by Bill being transgender[[note]] Probably helped by the fact that she's bisexual[[/note]](though she was creeped out that he dated Charlie before transitioning), and continues dating him after he tells her the truth (albeit for typically superficial reasons).
* FanonDiscontinuity: The post-Charlie seasons are disregarded by a lot of viewers. And even many who do like (or at least tolerate) the Walden seasons will ignore the series finale due to it turning Charlie Harper the character into a psychotic JerkWithAHeartOfJerk and the many fourth wall-breaking potshots at Charlie Sheen the actor.
* HarsherInHindsight:
** Some of Charlie's antics have creepily become real, as in 2009, Charlie Sheen had to go to rehab for personal problems and his marriage took a turn for the worse and later ended in divorce.
** Creator/JonCryer's ex-wife was reported to have hired a hitman on him. When Charlie asks Judith if he wanted Alan dead, this gives an odd dose of realism to the joke.
** Also, Charlie once mentioned that he'd rather close his eyes permanently than give up alcohol. It was funny at first, until Charlie Sheen got kicked off the show due in part to his drunken antics and his character got KilledOffForReal in the series finale.
** In an early episode, Charlie wakes up hungover and remarks that he's either extremely hungover ''or has been hit by a train''. [[spoiler:Subverted when it is revealed that Charlie didn't die from getting hit by a train.]]
** In "A Pot-Smoking Monkey", Jake and Charlie discuss whether or not anyone will come to Charlie's funeral. When Charlie dies, his funeral is largely made up of angry ex-girlfriends who are there to either make sure he's dead or spit on his memory.
** In "Working for Caligula", Alan jokingly remarks that Charlie will be the first of them to die.
** All the jokes about Charlie's promiscuity and all those women who catch sexually transmitted diseases from him take a crazy dark turn when it's revealed that Creator/CharlieSheen is HIV positive in real-life.
** Seeing Jake score with an older woman in the Season 9 episode, “Not In My Mouth!” might seem cool in the context of the show. However, when you think about the fact that Jake lied about his age - she’d face dire consequences for having sex with a minor.
* HilariousInHindsight:
** Judith's bitchy antics post-divorce become this when her actress Marin Hinkle plays a traditional housewife horrified by her daughter's divorce and separation in ''Series/TheMarvelousMrsMaisel''.
** "Trust me, darling. I promise to stick around long enough to identify your bloated, gin-soaked, syphilitic remains."
** A throwaway exchange from "A Pot-Smoking Monkey" takes on a whole new level of hilarity with the season 9 premiere:
--->'''Jake:''' If you died, would any of those women be at your funeral?\\
'''Charlie:''' As a matter of fact, a lot of them would. Granted, [[{{Understatement}} a few of them]] would just be there to make sure I'm actually dead.
** The entire episode, "The Devil's Lube", where Charlie imagines what his own funeral would look like, and thinking he'll die unhappy, decides to marry ''Rose'', of all people. Well...
** In one episode, Charlie mentions to Alan that the only people Jake hangs out with besides them are military recruiters. Guess what happens to Jake at the end of Season 9?
** When Angus T. Jones became a born again Christian and apologized for calling the show "Filth" the episode that aired shortly after the incident "I Scream When I Pee" had Jake proudly announce that he has the clap.. (And keep in mind Jake knew very well that he now has an STD but is proud that he has something "sexually transmitted".)
** In Season 10, Walden pretends to be a poor man named Sam Wilson, and Alan scorns him for living a double life. In Season 11, Alan ends up doing the same thing by pretending to be Jeff Strongman.
** For many seasons, it's believed Rose [[spoiler:murdered Charlie.]] Creator/MelanieLynskey, the actress who played Rose, got a new level of acclaim and recognition by playing a character on ''Series/{{Yellowjackets}}'' who [[spoiler:actually did murder her lover]].
* HoYay:
** [[ParodiedTrope Parodied]] in one episode when Charlie and Alan pretend to be gay. Alan gets rather too into it, whilst Charlie repeatedly denies anything in that direction, [[{{Squick}} naturally squicked]] due to the fact that they're brothers.
** Alan and Walden keep ending up together, with one of them naked. And Alan had a "problem" in the morning.
%%** Alan and Herb's friendship.
* InformedWrongness: In one episode, Alan wants Charlie to let his girlfriend move in with them. Although Charlie is portrayed as unfair for refusing, he does have very good reasons for saying no: chiefly being that it isn't Alan's house - it's Charlie's, Alan contributes little if any financially, and Charlie is already letting Alan and his son Jake stay rent free. Of course, Alan still lets his girlfriend move in without telling Charlie, then holds a party without asking.
* LesYay: Kandi and Lindsey end up in bed together at the end of "I Scream When I Pee" when Kandi tried to convince Lindsey that [[MistakenForCheating Alan rejected her]].
* MemeticMutation: Season 2 Episode 9's "Can You Eat Human Flesh with Wooden Teeth?" scene where Alan and Charlie [[SomethingWeForgot left Jake behind]] is this with the series, [[https://knowyourmeme.com/memes/i-think-i-forgot-something being used as a meme template]].
* MoralEventHorizon: For Rose, it's killing Charlie, no matter how much of a jerk he was and how crazy she is.
** [[spoiler:"Of Course He's Dead" (the GrandFinale) revealed that Charlie did not die (although Rose ''did'' try to kill him) but was kept in a dungeon [[Film/TheSilenceOfTheLambs Buffalo Bill-style]], which may still count.]]
* NightmareFuel: The season 3 episode "Hi, Mr. Horned One" is really disturbing to watch as Charlie dates Isabella, a wild, sexually uninhibited, spooky, Satan worshipper.
* NoYay: While a small (but vocal) minority of fans did legitimately ship Charlie and Rose, most viewers were deeply unsettled by their relationship and the eighth season's repeated rationalization of Rose's prolonged stalking and often violent and malicious behavior as "sticking by Charlie all these years". This, coupled with the fact that [[spoiler: when they actually got their RelationshipUpgrade, it was directly the result of Rose's machinations and they never spent even a moment of screentime as a mutual couple]] was the target of heavy criticism and actually could've conspired to end the show had the ReTool not been necessitated.
* OvershadowedByControversy: For its first eight seasons it was seen as a fairly standard-issue sitcom -- albeit one with an unusually high proportion of {{jerkass}}es among its characters -- but nowadays it's virtually impossible to discuss the show without talking about Creator/CharlieSheen's (and, to a lesser extent, Angus T. Jones') CreatorBreakdown and subsequent exit.
* ReplacementScrappy: Walden is seen by many as a poor replacement for Charlie, mainly because he wasn't Charlie, but also because Creator/AshtonKutcher's comedy style just doesn't seem to fit in with the show, and his interaction with the other characters feels rather forced and unnatural.
* SeasonalRot: While many argue that it happened earlier in Seasons 7 and 8, due to the jokes becoming more juvenile and asinine and the three titular characters becoming more {{Flanderized}}, it is near-universally agreed that it was Season 9 that saw the show permanently go downhill. The ninth season, produced following the public meltdown and departure of Creator/CharlieSheen, is largely considered this due to much worse writing and extreme {{Flanderization}}: Alan becoming more immature and an even bigger mooch, Jake smoking pot and becoming even more stupid, Rose becoming more a bitch, Lindsay becoming crazier, and Berta being the only character who stayed consistent. The tone is completely different, there's a much greater emphasis on ToiletHumour, and Charlie's replacement Walden is little more than a rich and more immature version of Alan and his interactions with the other characters feel very forced and unnatural. The remaining seasons improved somewhat by retooling the humor in a way that clearly took inspiration from ''Series/TheBigBangTheory'' (which at least was more appropriate than the toilet humor, given that Walden was meant to be a technology mogul), but it never again reached the levels of popularity it had in Seasons 1-8, and eventually ended with a widely-reviled finale that mostly just took pot-shots at Sheen. To emphasize this point, every episode from the first eight seasons on IMDB is rated between 7.2 and 8.7, with every season having at least a couple highly rated episodes. Seasons 9-12 pre-finale, however, has every episode rated between 5.3 and 7.2. And of course, the finale episode crashes through the floor, rated 3.8.
* StrawmanHasAPoint:
** We are supposed to side with Rose, whom Charlie has thrown off like a fake dollar eight years ago, and her ruining Charlie's dates and stalking his ex-girlfriends ought to be LaserGuidedKarma punishment for his Casanova attitude. But Charlie is right; Rose has been ending her relationships. JerkAss as he is, he does tell the truth.
** When Walden [[spoiler:starts dating Rose]] in Season 10, Alan is treated as completely unreasonable for repeatedly telling Walden not to do so.
* TheyChangedItNowItSucks: Creator/AshtonKutcher replacing Creator/CharlieSheen, some fans are claiming that while he is a talented actor, he just doesn't fit into the show very well and comes across as a PoorMansSubstitute. Some people also feel this way about the new decor of the set.
* TheyWastedAPerfectlyGoodCharacter: Judith's sister, Liz, only appears for one episode, which can be seen as a huge waste of Creator/TeriHatcher. There's a plot hook where it turns out that Liz was Alan's first choice before he got in a relationship with Judith, but it goes nowhere beyond that. It's especially odd that she doesn't even appear for the episodes surrounding Judith and Herb's wedding.
* TheyWastedAPerfectlyGoodPlot:
** Charlie and Rose moving to Paris. It could have been left as resolution for their arcs while still removing Charlie from the show. Instead, Rose finds Charlie in bed with another woman and throws him in front of a train, then practically gloats about it, becomes TheArtifact without Charlie and starts stalking Walden.
** Mia's return was hyped up as a {{Cliffhanger}} to close out the Season 6 finale, but gets completely thrown out the window in the first episode of season 7.
** For some, introducing Ashton Kutcher as a new character instead of TheOtherDarrin. It would have been a far better TakeThat to Charlie Sheen than anything they actually ended up doing, and would have kept the show's original tone.
** It's [[TheUnreveal never conclusively answered]] as to whether Judith's daughter Milly is actually Alan or Herb's daughter. Most of the signs seem to point to [[spoiler:Alan]].
* TooBleakStoppedCaring: To put it curtly, the casting crew is just a plain mess. The two main characters, [[DesignatedHero Alan and Charlie]], are hardly much different from the other selfish {{Jerkass}} characters on the show, which makes it confusing for the audience on who exactly they're supposed to be rooting for.
* {{Wangst}}:
** Alan. He often complains about how Charlie has casual sex and has a better life than him.
** Charlie's reactions to Chelsea wanting a breast reduction surgery to deal with back pain are beyond absurd. He acts like it's the worst thing that could ever happen, and even ''cries'' over it!
* TheWoobie:
** Alan. Pretty much the last few seasons consist of him getting repeatedly screwed over in some way, he was almost DrivenToSuicide in "It's Like Working For Caligula", his son is quite possibly the most disrespectful and unappreciative teenager ever portrayed on an American TV show, his brother tends to be an asshole who mostly coasts by in life, his mother is an unrepentantly horrid EvilMatriarch that can't see any flaws in herself, his ex-wife is a bitch that said she'd rather die alone than be with him, the list just goes on and on. It's sad that Chuck Lorre really makes him a live action [[ChewToy Meg]] [[WesternAnimation/FamilyGuy Griffin]].
*** Of course, some people see him as a JerkassWoobie due to his sponging off Charlie while constantly criticizing every aspect of his life and biting the hand that feeds him, as well as his becoming a [[AbusiveParents horrible father]] to Jake.
** Charlie himself is a JerkassWoobie. After all, he too grew up under the thumb of the same narcissist who drove his father into an early grave and constantly abused and neglected him and Alan their whole lives. Even as an adult, she still treats him like crap and has made him unable to ever have a meaningful relationship, which has often come back to bite him. Not to mention that his brother constantly mooches off of him and does nothing but criticize him. This is all PlayedForLaughs.
** Jake is another JerkassWoobie to some extent. Although he becomes an increasingly selfish LiteralMinded ungrateful dumbass over the course of the show, it's hard to blame his bitter attitude considering his mother thinks he's a burden and she and Alan both openly give up on him, stop caring and can barely tolerate him. While this is PlayedForLaughs, his life could have easily gone a different direction if his family gave a shit.
** Walden Schmidt should count. His High School sweetheart told him she wants a divorce, which [[DrivenToSuicide prompts him to throw himself into the ocean and try to drown himself]], only to pull himself out because [[MoodWhiplash the water was cold]]. That's enough there.
** And Herb. He's probably the [[NiceGuy nicest and most decent guy]] in the whole show, and suffers all kinds of abuse from Judith, not to mention his daughter Milly might not even actually be his. Ramped up to eleven after Judith [[spoiler: divorces him]].
** Whenever we're reminded of Louis' life as a foster kid. Especially on Christmas!
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