This isn’t the first criticism I read that said that the movie was "too shallow", but if I’m being entirely honest, I think you’ve missed the point. I don’t think it’s TRYING to make a deep statement. I think the only question this movie is concerned with is, "How bad and for how long does a person have to suffer before they decide that being a clown-themed crime lord sounds like a great idea?"

In just about every other origin story for the Joker, either invented by a comic writer or the character himself, the turn from mild-mannered comedian to clownish psychopath is sudden, and more than a little absurd. "All it takes is one bad day", he repeats in the classic Killing Joke comic. Except that never made any sense to me because lots of people have awful days every day, and none of them turned into Jokers too. Todd Phillips’ Joker says no, it doesn’t take one bad day, it takes thirty or forty years of sustained misery, that suddenly get catalyzed by a slightly-worse-than-usual week.

Even that Hot Topic-ready quote: "I used to think my life was a tragedy, but now I realize it’s a comedy", I think is actually more profound than people give it credit for. In most stories about an otherwise decent person degenerating into a killer, like Breaking Bad or Taxi Driver, there’s a turn: a moment where they are given one last choice to back away and stop the descent, but they choose to go forward and become the villain instead. That’s tragedy all the way back to the Greeks. "I know the right thing to do, but I’m choosing to do the wrong thing anyway".

Joker doesn’t have that turn. At no point does Arthur Fleck reckon with what he’s done or what he’s about to do. In fact at one point he admits he feels no remorse whatsoever, nor does he even feel remorse that he doesn’t feel any remorse. Transforming into a killer is empowering for him, and he delights in the chaos that his actions have wrought. It’s not a tragedy because there was no possibility that he could have turned out any other way. His life is a stick of dynamite with a long fuse, that’s been burning for years before the camera even started rolling, and we’re tuned in just in time to see the boom.

It’s not a particularly deep movie. It’s not trying to be. All it cares about is building a stack of cards so it can knock them down, and I think it does that exceptionally well.