Even in already-popular places I think there is something about “getting the photo” that gives people this kind of tunnel vision where they’ll behave in ways they might not otherwise. It has been noticeable living near and regularly walking/running across the Brooklyn Bridge and through the Front and Washington viewpoint in DUMBO, before and after the rise of Instagram. People are aggressive, selfish, and absolutely unaware of others as they try to get their version of a photo that is taken tens of thousands of times a day.