Did you ever have an arch enemy when you were in school? Maybe you have one now? What were the reasons for your conflict?

I remember having an ongoing spat with a conceited Ukranian kid called Mark. This culminated in me whipping his chair out from under him then having a full blown fight in the middle of a music lesson. Plus he was a Sega boy and I was Nintendo... it would never have worked.

So, who are yours? Maybe it isn't even a person?