The kids learn it from the parents.
I’d like to know who taught the adults of today that there’s no problem coming to shul 30 or 40 minutes late every single shabbos. People come in late with no sense of “bushah”. Then proceed to talk all during davening and then are the FIRST to grab a seat at the kiddush and take the largest helpings of food.
During the week, they come 15 mintues late to shul, spend the time “texting” and are the first to leave, unless there’s a yahrtzeit “tikkun”.
When the parents clean up their acts, then we can expect something from the children.