At what point does friction at school become bullying?

There seems to be quite a focus on school yard bullying these days, particularly since a student here in Australia died after a fight a few months back. So at what point does normal friction between students become bullying? At school, I was occasionally subjected to what may have been seen as bullying, but I appreciate it now for making me stronger. Is there a danger that we could go too far with new laws being proposed, and create a schooling system that is too controlled?