Gracesmum, precisely. Why should I want to be 'down with the kids'.
I never expected my parents/grandparents to know and understand my youth culture so why should I be expected to understand my children's/grandchildren's. I am not a disapproving old fogey, I am just not interested. I am quite happy that the generations below me have a different culture to me.
In fact not all children share the same interests. My children were teenagers in the 1980s. DS's passion was folk and protest music, DD's Hollywood musicals. It was a battle of could DD ramp up her Judy Garland music sufficiently to drown DS's Billy Bragg - and vice versa. The only pop group that ever interested either of them was Bon Jovi.