To put it into perspective: Cinemas in Japan are chill, it’s not like American or “Western” cinemas where people shout aloud at hyped scenes or laugh so loud where you can’t even hear what the dialog is or talk amongst themselves causing distractions (or yet, using their phone at max brightness that becomes distracting towards other viewers).
Instead: it’s more on immersing to a movie at your own desire, everyone for the most part is dead silent because they know that they are inside a cinema as courtesy is considered, while I’ve heard that is starting or has already started to decline in the US (& Western nations) since the experience of being in a theater isn’t the same as it used to be.
I often hear about people being loud, distracting, and using phones in theaters, but I rarely see it myself. It probably depends on what you’re going to see; when I went to see TMNT Mutant Mayhem, I went in knowing there would be kids, so I expected some chatter. When I saw Barbie a few days later, the theater was pretty quiet.
I go to the more expensive theater with big comfortable recliners now though because I can’t do cheap theater seats anymore, they are horrible for my back. Most of the movies I see are aimed at adults, so it’s probably partly the demographic.