There are a lot of ways in which this movie fails, but I want to point out this one in particular. Conflict between characters can be interesting when there are interesting points of view behind the conflict. This film, on the other hand, doesn't understand the use of conflict: the characters all just hate each other and bicker constantly. The movie tries to tell us these are friends and romantic partners, but what it shows us is a group of people that hate each other's guts, and not in an interesting way. Their bickering never advances the plot; it's usually just about whether they'll keep walking or stop for the night, and there's no difference between these options that we, as audience members, should care about.
Without a particularly interesting premise or compelling characters, this flaw sinks the movie from "nothing of interest" to "actually grating".
