In the 80's we had religious instruction at high school and for one hour per week, an old-school, fire and brimstone elder and me would sit outside somewhere (because there wasn't enough students in his class to justify giving us a classroom) and go through the yearbook or some other article that he chose.
In my final year of high school, religious instruction classes were not mandatory because of extra exams etc.
After missing just one of his classes, the elder caught me at the next meeting and informed me, 'I'm probably going to die at Armageddon if I continue missing his class'. I was 14 yrs old.
True story.
This is above and beyond the daily grind of being a teenage witness and my experience is very similar to that expressed by many other posters on this topic.
I could go on and on.