The people in a crowd photograph did not experience themselves as a crowd photograph.

Everyone in that photograph was in the middle of their own day. Somebody was worried about money, somebody was late, somebody had just had an argument and was still turning it over. The image compresses all of that into a mass, and we look at it as a single unit called the crowd, which is a description that existed for nobody who was there.

When you see a group photographed, pick one face and assume a full interior life behind it. Do the same in a room you are actually standing in. It is a small correction and it changes how you treat the people you are currently regarding as a general audience.