I was at school in the 7th, 8th, or 9th grade. They announced it over the loudspeaker during a break between classes. Everybody stopped, listened, then started walking again..... with their mouths agape (even the teachers). If they said anything, it was usually just, "Why?" Even in the days following, when people would try to make a reasoned explanation "The Cubans paid him", "The Russians paid him", "He wanted his face on TV". It was usually followed with, "But why?" Everybody loved JFK, and it didn't seem to make any sense at all.