Why do people scream so loud during concerts?

I have a movie of the Beatles during a concert. The audio was enhanced on it, but even then you could hardly hear anything because the girls were screaming so loud. I get showing enthusiasm, but screaming and shouting so loud you can’t hear the music you paid for? Some of those tickets aren’t cheap. I’m not just referring to Beatles concerts, but to any concert. Seems like they can’t enjoy the music and/or are preventing others from enjoying it.

(I think the Iphone link worked, I can ask questions now!)