Per wiki policy, Spoilers Off applies here and all spoilers are unmarked. You Have Been Warned.
It would be so easy to say that the whole damn movie is one gigantic depression trip and leave it at that, but that would be cheating (and wouldn't be doing it full justice). So, without further ado...
- Just the fact that at no point in the entire film does it deviate from its depressing and hopeless tone. Arthur lives a lonely and torturous existence, suffering from a mental illness that only alienates him further. As the movie progresses, and Arthur's abuse and tragedy at the hands of an uncaring society begins to pile up, he starts to lose his grip on reality while becoming increasingly unstable. By the time we reach the climax, Arthur (now the Joker) has lost both his sanity and any moral restraint. Even as he triumphantly stands over a crowd of admirers cheering his name, the music and tone make it abundantly clear that this is a tragic moment.
- (Pictured) The opening scene, where Arthur is so depressed that he has to pull the corners of his mouth up into the shape of a smile, which just doesn't do the trick. And if one looks closely, a Single Tear is on his right cheek, smudging his makeup a bit.
- Immediately following is a scene where a group of hoodlums steal his sign when he's doing promotional work as a clown. Arthur tries running after them (calling for help and getting no response), which isn't easy given he's wearing oversized shoes. Just when he thinks he's caught up to them in an alleyway, they smash the sign over his face. Followed by beating him until all he can do is lay on the ground in pain. To make matters worse, he looked like he was genuinely enjoying himself before they stole his sign, not just faking a good mood for the job.
- Afterwards, despite having bruises all over his body, his employer accuses Arthur of stealing the sign and dodging work because he finds kids stealing a sign and beating him up over it too implausible, and quite clearly assumes Arthur is lying because he is mentally ill, before declaring the cost of the sign will be cut from his paycheck. Meanwhile, Arthur can only stare and smile at him in tranquil disbelief and anger.
- This universe's Gotham just looks utterly horrible. The store Arthur is promoting in the beginning is going out of business, the trains are in a state of disrepair (with the light not working half the time), and everything gives off a sense of gloom and failure. The same goes for the citizens, who are at best completely apathetic towards the suffering of their fellow man. Much is said early on how not only are the streets filling up with trash, but they are being plagued by giant rats.
- Whenever Arthur's condition causes him to laugh uncontrollably in the most inappropriate situations that angers people he didn't mean to offend, with it visibly distressing and physically hurting him.
- Usually, the Joker's laughter is portrayed as campy, terrifying, or some combination thereof. Here, we see Arthur struggle with his rattling laughter, trying but failing to control it as it tears through him. It's the first time we see the Joker's laugh being this heartbreaking.
- On several occasions, the sounds and facial expressions he makes are indistinguishable from uncontrollable sobbing. Is he laughing to keep from crying, or trying to cry and failing?
- There's a scene where Arthur is on the bus and starts playing peek-a-boo with a baby who is staring at him, which makes the baby laugh. The mother then tells him not to bother her kid (which is sad enough, because he was making the baby happy), and he starts having a laughing fit. When she asks what's so funny, he hands her a card explaining he has a condition. Think about that — he had a laminated card to explain his condition in the 1980s. That's how many times something he couldn't control bothered/annoyed/confused someone; it got to the point that he had to go out and have a card specially made just to receive a modicum of understanding. To make it worse, the mother possibly doesn't even care about this explanation, as she turns around with an annoyed look on her face while Arthur laughs, like it's an inconvenience for her. Or perhaps it's pity on the woman's face. Either way, the scene really hammers in how Arthur doesn't really have a chance in the world of Gotham.
- Possibly the crowning moment is when he gets his first stand-up gig. Arthur gets a case of the jitters, which triggers a laughing fit that goes for a whole excruciating minute where he can't even put two words together. It gets to the point where he's struggling just to breathe. This scene can hit home to anyone who's ever done stand-up comedy and/or gotten stage fright.
- After hearing that he got attacked by some teenagers, Randall gives Arthur a gun to protect himself, which he carries everywhere. At the children's hospital, Arthur looks like he's having a lot of fun making the sick children laugh, when he drops the gun, and after trying to pass his fumbling attempt at picking it up as being part of his act, his boss fires him, saying that he's tired of all the complaints against him. Arthur looks completely devastated, especially since it seems like he actually enjoyed being a clown since it made people laugh.
- Making things worse: his boss reveals he knows that the gun was real and not a prop because Randall came to him and said that Arthur bought it off of him. That's right; Arthur's supposed "friend" threw him under a bus to cover his own ass. Hence why Randall ended up getting stabbed to death by Arthur after the latter finally loses his mind.
- Arthur's journal contains this "joke": "The worst part of having a mental illness is people expect you to behave as if you don't", with the words getting bigger and sloppier until we get to the "DON'T", written three to four times larger than the other lines, with a smiley face drawn in the O.
- Another quote from the journal: "I hope my death makes more cents (sense) than my life."
- A third one is also rather haunting: "Imagine your whole life ends on a sidewalk. I wonder how old he was. And how long no one cared about him for."
- When Arthur is with his psychiatrist, she despondently tells him that their current session will be their last, which prompts Arthur to reply with:Arthur: You never listen, do you? I don't think you ever really hear me. You just ask the same questions every week. "How's your job?" "Are you having any negative thoughts?" All I have are negative thoughts, but you don't listen anyway.
- You can actually see a bit of concern from Arthur's therapist as well. She isn't telling him it's their last session because she's given up, it's because the city cut their funding. She even states to Arthur that "they" (Gotham) don't care about him or her.
- Arthur having an Imagine Spot where he watches Murray's talk show in person. In the daydream, Murray hears Arthur's laughter in the audience and asks him to introduce himself in front of the crowd. Now in the spotlight, Arthur talks about how his purpose in the world is to spread joy and laughter, which touches the audience's hearts. Impressed by Arthur's optimism and positivity, Murray invites him onto the stage to the roar of the crowd, and tells him that he's always wanted a son like him. Then... we cut back to reality. It's painful to watch Arthur dream about something that will never happen to him. Granted, he does make it onto the show eventually, but we all saw how that turned out...
- When Arthur sees Bruce Wayne for the first time, he looks at him with genuine joy and tenderness in his eyes, thinking that this is his little brother and that he's going to be part of a family from now on, only to learn that his mother was a fantasist. This is the first time that the Joker and Batman meet, and they're friendly towards one another. Arthur, being a Friend to All Children, probably wanted a little brother as well as a father figure, hence his attempts to make the small boy on the train laugh and you can see that he's happy to make Bruce smile and laugh with his magic tricks. It's even sadder when you consider the fact that they will one day be arch-enemies.
- Arthur coming home from his first attempt at talking with Thomas Wayne to discover that his mother had a stroke while he was away.
- Soon afterwards, Arthur sees Murray Franklin talking about him on his show. Arthur's surprised and happy to see that Murray had a special bit showing him off... until he realizes the only reason Murray drew attention to him was so he could insult and make fun of him on his show. Arthur's expression quickly fades from happy to disbelief and then cold, hard anger. What's worse is that Murray was wrong; before cutting back to him, you could hear someone laugh at Arthur's jokes in the video.
- The heartbreaking reveal that Arthur was hallucinating Sophie's presence the entire time. She never went on a date with him, supported him at his stand up performance, or consoled him when his mother was in the hospital. He just imagined her because he needed someone to be there for him, when in reality, he was alone the whole way through.
- Arthur steals a file on his mother from her time at Arkham, and finds out that she lied to him about everything. She adopted him after he was abandoned, and both she and her boyfriend had horribly abused and neglected him. And as he's reading this, something within him finally snaps like a twig as he has another fit of uncontrollable laughter. It's not easy to pin down the exact moment that Arthur Fleck well and truly died and the Joker - the vengeful, homicidal Tragic Monster driven to make the world pay for what it has done to him - was born, but this would be one of many strong contenders... and even if it isn't, this is, without a doubt, a crystallizing step on his way there.
- You see Arthur's mother in a flashback and it's impossible not to feel sorry for her, too. She looks so utterly broken, with bruises on her face, and when the person talking to her asks how she could have left her son chained to a radiator, she explains she never heard him crying — she thought he was a happy boy. It's implied that, due to his condition, his constant fits of stress-laughter helped convince her he was just "happy."
- His mother's lack of support earlier on in the film hits pretty hard, too. Arthur is going on to her about how he's going to be a comedian, presumably in a bid both to cheer himself up and to make her proud. Her response?
- Making the matter with the file even worse? It's actually possible that Arthur's mother wasn't making it up that Arthur is Thomas Wayne's illegitimate son, and instead he used his money and connections to create fake adoption papers and get her confined as mentally ill to avoid having to take responsibility.
- It is implied the clerk at Arkham lied about Arthur needing Penny's permission to see the file, and then tried to wrestle the file away from him because he didn't want Arthur to learn the Awful Truth about his treatment by Penny.
- The scene at the hospital room with Arthur and his mother in general, but this line in particular:Arthur: Happy... [brief giggle] ...I haven't been happy one minute of my entire fucking life.
- The scene where Arthur rehearses his "knock-knock joke" for his appearance on Murray's show. Calling back to his joke about "his death making more cents than his life", his initial plan is to shoot himself dead on live television. When he practices his suicide attempt with the unloaded gun, he imagines hearing the audience laugh and applaud at his "final punchline".
- When Arthur makes his appearance as Joker on Murray Franklin's show, he's absolutely awestruck and even retreats back into Arthur Fleck to say, "This is exactly how I imagined it." He realizes that, as Arthur, he's finally fulfilled his dream of appearing on his idol's show and accomplished something with his life, but he's too far gone to savor the moment. Arthur doesn't exist anymore, only Joker.
- Before he shoots Murray, Joker tearfully rants about how he's a mentally ill loser and how society has abandoned him and treated him like trash, in case you needed a reminder where Arthur's Start of Darkness came from. When he calls Murray out for humiliating him earlier, he's just boiling with Tranquil Fury. The man he looked up to, the one who entertained him and made him happy, betrayed him just like everyone else in his life, and he's not gonna have it anymore.Murray: Not everybody, and I'll tell you this, not everyone is awful.
Joker (coldly): ...You're awful, Murray.
Murray: Me? I'm awful? Oh yeah, how am I awful?
Joker: Playing my video... inviting me on the show... you just wanted to make fun of me. You're just like the rest of 'em. - In a way, Murray's death is actually quite tragic. Behind the scenes, he's proven to be a pretty friendly guy who shows signs of encouragement to Arthur, even obliging to calling him "Joker" and allowing him to wear his makeup onstage. On top of that, Arthur finally gets to fulfill his dream of appearing on the show with Murray at his side and an entire audience cheering for him (he himself seems a bit awestruck once he takes a seat); sadly, Arthur is so blinded by pent-up rage that he single-handedly destroys his own fantasy-come-true and coldly guns down the man he once saw as a father figure.
- If there's one moment that earned Joaquin Phoenix the Oscar, it's undoubtedly the final "joke" he tells to Murray, right before gunning him down. From his facial expressions to his voice, you can tell he's running through a gamut of emotions, from fear, to anger, to despair, to pure hatred:Joker: (with sarcasm and a tinge of concern) What do you get... when you cross a mentally ill loner (voice goes to animalistic anger) with a SOCIETY, that ABANDONS him, AND TREATS HIM LIKE TRASH?! (voice tearfully breaks) I'LL TELL YOU WHAT YOU GET! (voice becomes seethingly hateful) YOU GET WHAT YOU FUCKING DESERVE!!!!
- If the look on his face right after is any indication, he's in shock at what he's just done. He then almost immediately goes back to laughing and shoots Murray's corpse just because he can, and then looks into one of the show's cameras to mockingly recite Murray's catchphrase, "That's life!".
- If there's one moment that earned Joaquin Phoenix the Oscar, it's undoubtedly the final "joke" he tells to Murray, right before gunning him down. From his facial expressions to his voice, you can tell he's running through a gamut of emotions, from fear, to anger, to despair, to pure hatred:
- At the climax of it all, with the city aflame and the Waynes murdered, Arthur finally wakes up from the crash. Everyone's cheering him on, shouting for the Joker. And he looks around, and what was hinted at comes into total focus: nobody cares. Nobody cares about why Arthur's lashing out, or what he wants, they just know he kills people, and they fight him or follow him because of that. Arthur thought people were starting to notice he existed — but no, they just noticed the Joker. Nobody cares about Arthur. Just the Joker. So, to demonstrate how much he wants people to notice him, Arthur takes the blood from his mouth, and spreads it across his lips, forming a bloody smile in front of the followers. The Joker can only laugh until he's sobbing.
- Which is more tragic? That Arthur now has to play the part of the Joker to be noticed, or that all that is left of Arthur is the Joker?
- To add more to the tragedy? Arthur right then accepts being the Joker, knowing that if he wants to be acknowledged, to be noticed... to know people know his existence... then he must fully become the Joker.
- The simple fact that, like everything else about it, Bruce's parents are killed in front of him by Joe Chill, who had taken the words of the Joker in face value ("Hey, Wayne! You get what you fucking deserve."). The simple shot of the now traumatized orphan standing next to the bodies of his dead parents... with the knowledge of what he will eventually become.
