It has happened with me many a times. You too would have noticed it sometime or other. Sometimes silly and cliched acts when done with gusto end up having their desired effect.
A speaker rises on the platform and says hello. Audience yell back, somewhat disinterested, half-heartedly. Then speaker speculates on unfortunate event of audience missing their breakfast/lunch that day and urges them to again say with more enthusiasm. This time, roar is louder. Rinse and repeat. Even louder. Do audience really become energetic by this act of speaker? Or they just do that to stop him/her to repeat endlessly? I have a feeling that it's former and yet I also know annoyance that arises from such actions of speaker.
Once a professor found us students drowsy at 8'0 clock class in the morning. She asked us to clap thrice in rhyme of 1-2 1-2-3. Yeah right, we are 5 years old. Yet you know, we were awaken. Was that energy in professor's voice, novelty of her approach, mere noise of our clapping, or, as appears to me, real abandonment of laziness?
Consider annoying as hell 'good morrrrrrrrrrrrrrrning' of Lagey Rahe Munnabhai. As irritating it may be, I expect it to have effect of refreshing listener.
Seems like that enthusiasm, howmuchever over the top it may be, tends to diffuse to audience, even when they don't want it. It's a good thing, I think. Same, of course, applies to hatred. We are not in as much control of ourselves as we'd like to believe.