what the shit just happened?

well my friend invited me to watch YJHD with her college friends. the song balam pichkari started and suddenly two girls jumped out of their seats and started dancing beside the screen following which everyone started dancing - yes my friend and her college mates as well - tried dragging me too but i didn't got up. but is this kind of behaviour is appropriate in theatre like PVR? and what is happening to the youth? This is Centrio Mall🙂