Elevator Etiquette

Okay, I’ve lost the ability to understand what it ws that I’m supposed to do in an elevator when it stops on a floor and there are people waiting to get in and I’m waiting to get out. It used to be that the normal behavior was for the people outside to wait to get in until the people inside got out. That’s gone by the wayside. I was in an elevator in Hatcher the other day and a whole troop of people started pouring onto the elevator before I could get out. I’m honestly clueless here. Do I just barge out and rudely shove the people waiting to get on? Do I stay on and push through the wall of people after they’ve already boarded? I don’t get it.