Insomnia (2002)
aka the Nolan film noone remembers in between Memento and Batman Begins
It seems like what I got out of this movie has nothing to do with what other people get out of it. So this is a remake of a Norwegian film about a homicide detective who's a giant piece of shit and goes to this place in Alaska where it never gets dark and he can't sleep. The killer gets compromising information on him and he's forced to work with him. The remake tells the same story, except the main character is somewhat more likeable.
By which I mean he's just a good man thrown into a terrible situation with a genuine moral dilemma, and you're watching him get tortured by lack of sleep for about a week, and it's depressing af. It's actually one of the most depressing movies I've ever seen. So if the goal was to make him morally gray, I'd say the movie utterly failed because it didn't even occur to me to judge him. And conversely, if someone is watching this and goes like "oh yeah this guy definitely deserves what's happening to him", I'd just be like what the fuck.
Like, I don't know how other people work, but for me, judging someone requires that they make clearly wrong choices, so if it's completely unclear what the right choice even is, that doesn't apply. And it's been established that (unlike in the original) the trouble he got in wasn't his fault, either.
Also the movie is quite beautiful in terms of setting and atmosphere. And great performances. Which all just makes it more effective in being depressing.
So what's the message? I don't really know or care. What I got out of it was just feeling very sad. Is that good? I'm not sure. This is generally a confusing question. But arguably that's a state of mind that people do seek out. And fwiw if we did just go just by intensity of emotions it evoked, this would be #1 among Nolan movies. We don't go by that of course, so idk how to rate it.