A bit of deference from kids and teenagers would be no harm at all.
societies where deference to elders is a deeply held value do suffer a lot from it.
*I hate if I'm sitting on a bus and there are elderly people around and a group of teens are cursing and swearing like troopers. It's so disrespectful.
Who's defending that? The idea that your child shouldn't curse loudly on a bus can be universally applied. That doesn't just apply to children. That is in fact courteous, polite behaviour which I would of course support. It's deference that I don't support.
Also, I remember telling a friend about how my frail father who used a walking stick had to stand for the entire journey once on public transport while well dressed business men and women ignored him.
and that's appalling. My child would get a stern nudge to move if such a man was standing near her. And she'd be told that next time she better not wait for me to tell her.
my DD is very energetic, but she is constantly reminded about watching her step around older, frailer people, and she is getting more aware of it. Her grandparents are also getting more frail, and she feels the connection I think.
But all those examples have nothing to do with deference for age itself. they are examples of being empathetic to someone in need, and pretty much everyone on this thread has said that's a good thing.