Well, the Phoenix Symphony certainly seem to know what they're doing. Trust me, I'm grade 3 piano and that guy they got in to do the Rachmaninoff is very fast. Just as fun was the bar we went to afterwards where the karaoke machine was running full tilt. It must have been gone 11pm but there was still a family around to walk out disgusted at drunk-guy-at-bar's excellent recall of Eminem lyrics.
I've also seen people walk out of the dreadful Primeval and I don't think it was because it was such a terrible film either. However my favourite disgusted American moment was during a screening of Borat in Prescott last year. The couple walked out at the end of the naked wrestling scene. That was a pretty long scene.
In all, I think that while Americans show a lot of promise at being appauled, outraged and sickened, they really ought to work on their execution some more.