I'm doing research on movies where unplanned elements bring something new to the story.
It's hard to know this just by watching a movie, and the usual Google search only brings up short scenes or an actor's fleeting improvisation. However, I'm more after something more significant, like a whole movie influenced by uncontrolled circumstances, where the actors improvised all their lines, or where significant changes were made (for the better) due to accidents or unplanned events.
Off the top of your head, do you know any such movies? Thanks!