The vast majority of critics and (thus?) moviegoers reacted differently, but I actually consider American Hustle to be an effective argument against improvisation in films. Because, whereas I'm a great fan of it when it's executed amusingly by talented stand-up comedians, unscripted babble can thoroughly blacken a film's quality – and that's exactly what happened with this one.
David O. Russell has an increasingly strong penchant for preferring characters over plot, which he and his actors have stated numerous times and which worked in some of his earlier stuff. However, the New York writer/director oversteps the bounds of aforementioned conversation technique in his 2013 release and makes it a hopeful contestant for the most boring "comedy" I've ever seen in my life. The almost two and a half hours of running time have a promising start with a ridiculously long take of Christian Bale adjusting his hair, but the only thing American Hustle remains after that is ridiculous. Each and every role is cast with a talented actor or actress, but in my humble opinion, this is irrelevant, as none of them are realistic, likable, or even interesting and impromptu doesn't suit any of them.
I haven't had a tittle of insight in the making of this surprising Oscar nominee, but, from what I saw on screen, I assume that the actors had a great deal of fun with it. Be that as it may, none of it relayed to me as an audience member and I was merely at awe how Russell could possibly neglect his task of directing that much, apparently delightfully accepting all ideas he was presented with, regardless of their absurdity. Some scenes, for example Robert De Niro's one and only, are totally void of sense and some of the biggest "Plot? Screw that." moments I can remember to have seen in all my life. The abundantly great amounts of improvisation would have led to something wholly incomprehensible and thus, Russell (due to his producers' demands, maybe) reacted the way you could expect: filling a perceived third of the film with explanatory voice-over, a trite and overused compensation for poor storytelling.
Granted, American Hustle does have good-looking costumes and set design as well as fine cinematography and editing, and if you find joy in the over the top of over the top portrayal of characters– well, go ahead, watch it. I just think that most of the people claiming to like the film are being overtly pretentious and following critics' opinions, since there isn't really anything about it to enjoy.