When I was at primary school, it was compulsory for religious instruction once a week. Everybody groaned and acted up a bit more than normal, but apart from that, everyone put up with it.
It turned out, however, that one of the teachers was a fundamentalist, and he always insisted that everything we were taught in science was wrong. Everybody had arguments at great length with him, and were sent out of the room for trying to have a debate about the fact that we must have evolved from monkeys because we have tailbones and other topics like that. Quite a lot of the kids got scared with some of the concepts that he taught us...
The crunch, however, came when the teacher was trying to explain the concept of sin. At the time, I was slowly rocking on my chair, and the teacher quickly announced that rocking on your chair was a sin.
This in itself was not so bad, but he went on to describe how people who sinned would burn in the fires of Hell.
Needless to say, I was scarred for life, and scared out of my wits by this little episode of life.
No wonder I'm here 8 years later writing about it!
Conclusion: If you want to really badly scare a kid, tell them that an everyday minor rule break will have them roasting in the fires of Hell. I swear that there will be a marked change in personality for the better... | 
