I don't pretend that the second of the following two frames is a great photo. I'm not even sure it will resonate with anyone who wasn't there. It is the better of the two. The former is no more than a snapshot, the latter at least aspires to be a picture. Just a few seconds separates the two exposures, but enough has changed to make a difference.
I don't want to over-analyse it, but the placement of the figures is better defined, the figure far right keeps the eye from leaving the frame, and fewer of gazes are aimed at the camera. The rhythm of the photograph has altered.