All the reasons listed in the negative reviews are what makes this movie an incredible cinematic experience. Yes it makes you feel anxious, frustrated, uncomfortable, and much more. It is not a happy go lucky Disney fairytale story, or the typical Hollywood formula, where everything works out for the protagonist in the finale. But what it is, is an experience, it will make you feel all those emotions and much more.
If they average movie bores you; if you're sick of movies with the exact same rigid categorical storytelling technique than this movie might be for you!