The phone OMFG
I think I ranted about this on here the last time I went to the cinema but I swear I was watching people as they came in and the second they sat down the phones were out and seemingly glued to their hands throughout the entire movie.
Now I know some people like to be available in case of emergencies and stuff like that but ok then turn on the phone set it to silent/vibrate whatever then put in in your pocket or bag fgs, there's really no need for them to constantly be in peoples hands.
It stretches a lot further than the cinema too, restaurants, shops etc.