does power cord length matter? fact or myth?

I have read somewhere in a forum that power cords need to be over a meter. I can't remember the reason and I am not sure it was correct anyway. Is this fact or myth? I have a 2 meter power cable that could be used in less than a meter and more than a meter with my system. Will this hurt the performance of the cable if cut in smaller pieces? Maybe brand specific? The cable is a Oyaide Tunami GPX