Can't remember if I already posted about it, but I finally saw The Joker just before the pandemic hit. The first time I saw it, I thought it was okay; second time I watched it, I thought it was awesome. Guess my point is, it's one of those movies that you might not like the first go around, but you appreciate the more you watch it. Phoenix was awesome acting-wise.
(Spoilers below)
There are also little clues in the movie that make it fun to watch, because as a viewer, you're basically trying to decipher what is real and what is fake. One clue is the clock. In many scenes, it says it's 11:11 -- in the beginning when Arthur is in the social worker's office, and when he flashes back to his time in the hospital and he's banging his head on the wall. It's also 11:11 when Arthur is leaving his job after getting fired and punches the clock. My point is, every viewer will read into it differently. The fact that it's 11:11 in the hospital, and the fact that the last shot of Arthur is him in the hospital, one can read it as the entire movie was simply in Arthur's head and never really took place. Also, the movie begins and ends the same way: with Arthur laughing as he's being interviewed by someone (notice the similarities between the social worker and the psychiatrist). I don't necessarily read it this way -- and there is more than one way to interpret it -- but the creators kept it open-ended that way, which is cool.
I think some things happened in the movie but other things didn't -- like the whole Joker Movement thing; that was just in his head. I also don't think he ever killed the TV Host -- he even says in that scene, "this is exactly how I pictured it," which implies that it's only in his mind. The only thing: the clock when he's sitting with DeNiro says 10:40, not 11:11 like in the other scenes. I think this was because the director wanted to leave it open-ended as to whether this scene was real or not -- like I said, I interpret it as not being real, but there's no right or wrong answer.
The one thing you're never sure of is, why he's in the hospital, especially in the beginning; and if the entire movie is just all in his head (and he's been in the hospital the entire time), obviously the answer wouldn't be in the movie.
Interesting tidbit: Tom Wayne calls Arthur "Pal" in the bathroom the first time he meets Arthur. He also calls the masked man who kills him "Pal" just before he's killed. So if the whole movie is "fake," that (murdering the Waynes) could be the real reason why Arthur is in the hospital the whole time.
Anyways, I could go on -- there are a ton of cool little things you start noticing the more you watch this movie, which makes it awesome. Like when Joker has blood on his feet, the clocks, etc. Also, pay attention to exactly what each character (the mother, Tom Wayne) says at key points in the movie.