The one that comes to mind is Maniac (2012). On first viewing, I actually kind of hated it. This film focuses intently on stalking, to the point that even the violence takes on this creepy, voyeuristic quality that I found disgusting.

But works of fiction that can force me to reflect on their content long after the fact is art that I tend to value. In this case, I think the cinematography succeeded in blocking the detachment I'd normally use to deal with horrifying realities. One of the film's victims was humanized in such a way that I felt like shit for hours after watching.

It took me a few months, but now the Maniac remake is something I'll even recommend from time to time. Well done.