I've been watching live sporting events in Toronto since 1993, at the Dome, at the ACC, and at the good old Gardens; and the only thing I've ever thought was lacking, was more fan participation.
Canadian fans (and I assume USA fans as well) sit back and watch the sporting contest as if it were a piece of theatre, or other form of entertainment. Whereas in Europe, the fan views himself/herself as part of the action, and believe they can create an atmosphere to inspire the team to victory. Therefore you tend to get songs, chants, flag waving, fireworks and flares being set off etc etc.
Obviously each to their own, and if it's not in the North American culture, then it may never catch on; but I know for a fact from talking to players and officials of the various teams that I support, that the fans' efforts are appreciated and do help inspire the team to perform better.