It was an excellent movie but there are multiple factors to consider:
(MIGHT INCLUDE SPOILERS!)
•This movie is extremely dark and horrifying but in a way where you still want to watch it till the end whether it's violent or horror or whatever the acting is so phenomenal to the point where your eyes are literally stuck to the screen you just can't stop watching it.
•This movie was amazing but it couldn't ever be the way it is now without the way it was presented the way it was presented really does put an impact on the way this movie turned out. Somehow the directors and producers and writers and even actors found a way to really touch the audiences and explain what the word "psychotic" really means! They presented it in a way where you felt sympathy for the Joker but at the same time you thought that he was INSANE for what he was doing!
•Another thing is that this movie is dark to the point where Arthur Fleck (the Joker) enjoyed killing because it was his way to show that people couldn't step all over him and that he would snap back! Another example of how dark it is, is shown by the line "I thought my life was a tragedy now I realise its a f***ing comedy" imagine how dark it is to showcase that TRAGEDY=COMEDY so I wouldn't recommend this movie for someone who's really sensitive and can't handle a lot of violence and torcher you could say because Arthur Fleck (the Joker) was going though basically mental torcher.
•Maybe adding the line of ONE BAD DAY would've been good because the whole movies point is that one bad day is all it takes to drive a normal person completely insane and the Joker's proof of that.
•The phenomenal performance by Joaquin Phoenix literally made people scared looking at him because his performance made some people think that he was actually like this in real life and to do such a performance is really legendary because I don't see a lot of actors doing that nowadays.
•Yes while this isn't the story we have all heard ever since we were little kids about the acid and all that this movie was still phenomenal in its own way because honestly it showcased the modern world how people bully others driving them insane and then question why they act that way and personally I liked this storyline better then the acid one (my opinion though everyone has there own opinion)
•This movie made the Joker relatable and I know that sounds truly terrifying but in a sick odd twisted manner it isn't like the movies where heroes save the day it really made (at least it made me) understand why the Joker is who he is and why he acts the way that he does and the fact that this happens to real people is terrifying. It also shows that not every villain is responsible for the way they are because sometimes its the society that drives them psycho
All points considered I would say this is a must watch movie and I definitely recommend it