Selfies are a weird thing. You get a bunch of people and have somebody take a picture of them, they just stand there and smile. Give somebody a selfie stick and they all go crazy.
Here’s whey I think this happens. When somebody in taking a picture of them, they are not part of the group and the group tries to be nice. It’s like Bill Preston in the “Let It Be” movie. He comes in and the band in on their best behavior. Without him there, they fight all the time.
Give somebody a selfie stick and the group don’t have to worry about outsiders. They can act whichever way they want.