exactly my point. does primal fear show richard gere or edward norton go for a change in behaviour. does 'anatomy of murder' show james stewart go for a change in behaviour. no. because if the former was a psychological thriller, the later was a investigative thriller. the crime was not shown to keep up the suspense. whereas, in 'billboards' the main characters undergo a gamut of behavioural changes. the crime is not shown because it has nothing to do with the crime at all. the crime is just a symbol of tragedy, a symbol of spark to get things going. first 30 minutes into the movie, do you, by any extreme stretch of imagination, imagine that the characters of mcdormand and rockwell would end up going on a journey together in the end. no. complete diverse and complex characters. to be more specific, the two would have even been villains in any other movie. you have a foul-mouthed mother who refuses her car to her daughter and even sportingly agrees she gets raped. and you have a racist police officer who has no respect for the down-trodden or the meek. and what happens is both undergo a humanitarian change under the circumstances they have to endure.