Since the entire Joker film is told from the perspective of a man whose grasp on sanity only loosens over time, a lot of moments between Arthur Fleck and the other characters is up for debate.
- Was Randall planning to get Arthur fired by giving him a gun? Or was his concern for Arthur's safety genuine and he only acted selfishly once the gun had been discovered? Or even a third possibility, that he may have been planning to rope him in on something illegal. He did say that Arthur could "pay him back later".
- Given how sleazy this version of Thomas Wayne is portrayed as, it's still not totally outside the realm of possibility that he really did forge documents to cover up his relationship with Penny, and Arthur truly is his son. It would explain why Penny is diagnosed as a Narcissist despite not displaying any of the traits outside of being a possible fantasist with a Lack of Empathy. Also, Thomas and Arthur look vaguely similar, both tall and pale with black hair and aquiline features.
- Though this one goes both ways: The only two times we really see Thomas Wayne are during an interview following the murder of three employees of his, wherein he makes some tone-deaf and classist comments, and in a confrontation with a clearly unstable man who made unsettling approaches to his young son, physically assaulted his butler when confronted and, upon seeing him, started yelling about being his son and demanding hugs. Under the latter situation especially, he's unlikely to be in a particularly warm and cuddly mood.
- Assuming it even happened the way we saw it. Bear in mind Bruce's playground is right by the road, near a fence, and far from the mansion. Arthur gets his fingers in Bruce's mouth before Alfred and Thomas show, when we don't see any sign of them being present. If they were both watching Bruce, how is that possible?
- We're never given any indication that Murray personally made the decision to have Arthur's video on the show nor to have him personally appear on the show as a target for mockery, and he seems quite friendly, and is shown to be uncomfortable with mean-spirited humor. It's possible that he died for a decision made by his producers that he didn't even approve of. This would be explained by his "You don't know the first thing about me, pal," before Arthur's final "joke". By the same token, one could interrupt his "You don't know the first thing about me, pal," as him saying that because he couldn't actual retort Arthur's point that he (Murray) was only brining Arthur on the show to mock him some more.
- Also, when Arthur demands to be called "Joker" in his introduction, he meaningfully refers back to Murray using that very name to describe him. Murray appears to genuinely not remember using it, and neither does his producer. Is he just bullshitting Arthur, does he not remember making the joke because he makes so many in his career, or does he not remember it because it genuinely didn't happen and Arthur merely imagined it? It's also likely he didn't really react because his mockery wasn't that bad in Murray's head. He even invited Arthur to his show the next week, which is incredibly supportive even though Arthur sees it as just more humiliation. Not everyone mocked by a comedian on TV gets a guest appearance later, especially so soon after the mocking; it gives Arthur a better chance to break out as a comedian than he thinks.
- Which Murray is the real Murray? The one who treats his guests well and encourages their creative choices even when his producer tells him otherwise, or the one who punches down for the sake of getting a cheap laugh and only draws the line at jokes that would jeopardize his ratings? At the very least, he's decent enough not to try and make jokes about real-life tragedies. He also talks about having good clean family humor but doesn't seem to think publicly humiliating Arthur was/is mean spirted. Were the jokes he made about Arthur just intended to be good nature jokes that he just simply didn't realize had hurt Arthur's feelings or is he just a hypocrite when it comes to his philosophy about good clean family entertainment? A third possibility surrounding that is Murray maybe realized he was wrong to make fun of Arthur and was inviting him on the show as a means of an apology.
- How aware is Murray about how bad Gotham really is? As a talk show host, he has to be caught up on what's going on so he can make jokes about it, as shown by his quips about super-cats for the super-rat infestation, and he is right that there are decent people in Gotham. At the same time though, his "Not everybody is awful" seemed to have been his only argument against Arthur's still sound criticisms (he stopped talking right after, which gave Arthur the opportunity to call him awful), and even if there are decent people, this is glossing over the fact that the city is a crumbling cesspool where those decent people are trapped and bullied in shitty conditions by elitist assholes. Is he aware of how bad things are, but still has hope it can change, or someone who only superficially understands the dire circumstances and thus is holding onto an oversimplified hope?
- Did Arthur already plan on shooting Murray after the suicide rehearsal, or did Murray making fun of him for using a 'Knock Knock' joke make Arthur change his mind about killing himself and instead go on his rant and then kill Murray?
- Was Arthur at least partially aware that Sophie spending time with him was all in his imagination? Perhaps his hallucinations of her were his way of keeping himself some form of company, and his act of barging into her apartment was his way of affirming to himself that his fantasies with her were just that.
- How far do Arthur's delusions spread beyond his imagined relationship with Sophie? How much of what we see is real? Did he really deliver an impassioned monologue that explained his motives? Were there really riots in his name? Hordes of clown-clad followers? Or is that what it takes to be as much of a psychotic megalomaniac as the Joker — a delusional belief that everyone's in your corner?
- At the end of the movie, has Arthur truly found happiness in his newfound role as The Joker? Or has he given into the role out of some morbid sense of obligation, having realized that nobody ever really cares about him, but just the persona he developed? Right as he paints a bloody smile over his mouth, you can clearly see his eyes are watery, though they may be tears of joy, and the aforementioned smile can be interpreted as a Broken Smile.
- Is the whole movie just another origin story that the Joker has invented for himself, taking place in his head in the future? If is the case, is that why Thomas Wayne has taken a level in jerkass? Could it be that the Joker remembers him as being worse than he actually was? Or does the adult Bruce Wayne remember him as a better man than he actually was, due to never having seen how he treated other people and the fact that Gothamites remember him as a hero of the downtrodden? A combination of both?
- "When I was a little boy and told people I was gonna be a comedian, everyone laughed at me. Well, nobody's laughing now!" Was that Arthur's attempt at an actual joke (albeit presumably cribbed from Bob Monkhouse)? Was he reading the crowd during his botched standup, hoping to try and at least get some ironic laughter through that statement? Was his anger at Murray because he believed Murray had deliberately missed the point of the joke to make fun of him?
- Related to Arthur's joke itself. Was this sentence the full joke he intended to tell, or did he write something longer which included an actual punchline he couldn't get out due to his fit of laughter?
- When Murray finds out that Arthur/Joker started the clown riots, instead of having security escort him offstage right away he decides to give him a dressing-down. Was Murray's sense of conviction genuine or was he just hoping to squeeze a bit of good publicity out of an incident that could very well have jeopardized his television career? Interestingly enough according to the leak, in the original script, Murray's producer told him to stop the interview with Arthur but Murray insisted on keeping it going because he might win an award for it.
- Even Arthur's laughing condition is subject to this. Is he merely subject to an involuntary mental tic that is completely out of his control despite how he is genuinely feeling, or does he genuinely have a sadistic, cruel sense of humor that such a condition can be conveniently used to excuse?
- In the scenes where Arthur laughs due to his condition, his laughter sounds forced and he's usually shown with a pained expression. When he laughs deliberately, he sounds more natural and smiles.
- How much of the big confrontation with Murray was actually real? While we could assume that it all happened, it seems a bit too convenient and cathartic that after all of this time, Arthur gets to say exactly what's on his mind and spill out all of his problems onto Murray, the back and forth went as smoothly as it did, not to mention that he got the last word on the argument. This could also explain why once Murray believed Arthur's story he didn't just call security as soon as Arthur confessed to murder. For all we know, Arthur could have made up the entire confrontation in his head, the same way how people think up fictional arguments and hypotheticals that are very self-serving.
- Murray Franklin is obviously based on Johnny Carson who was a cultural institution at the time the movie takes place. Carson so dominated the late night airwaves that only A-list celebrities were main guests. The second or third guests were usually up and coming comedians. Johnny Carson had struggled himself and had scouts scour clubs to find comedians like Jerry Seinfeld, Eddie Murphy, Ellen Degeneres, and many more who had tremendous potential so they could have an enormous opportunity. He would never have wasted time during his monologue to show a video of an amateur bombing on an open Mic night at a small club, much less later inviting him on the show just to be a guest without even doing a set. We already know Arthur had delusional fantasies about being on Murray’s show, this pretty obviously seems like another one.
- Is Hoyt really a Mean Boss who had it in for Arthur? Or is he a business owner struggling in a broken economy who can't afford to keep an employee who was so reckless as to bring a gun to a children's hospital? For that matter does he actually like Arthur like he claims and simply is losing his patience at him over both perceived and real issues with him?
- Was the clerk at Arkham Asylum really not allowed to let Arthur look at the files about his mother's abusive behavior? Or was that a lie and he genuinely didn't want Arthur to be traumatized by learning about his sordid past? Tying in with the latter, It is worth noting that the clerk seemed to have no problem possibly giving Arthur the paperwork till he started to read the files and he then had a very noticeable Oh, Crap! look on his face.
