Does anyone watch ellen?

Why are people there always screaming? I have watched it a few times. I don't understand how people are so hyper all the time? There are always screaming "Woooo.." beginning of the show, beginning of commercials, returning from commercials, end of the show, they also scream for everyone that come on the show. It seems like if a homeless person accidentally enters the show, they would scream for him too. Are they being directed to be like that? or is it how the people are in their culture? you know like celebrity crazy? Thanks.