What Makes a Good Villain?

I've just finished writing another novel and created a super nasty piece of work.  There’s no namby pampy ‘psychologically misunderstood’ or ‘aw, isn't the vampire/serial killer/criminal just unhappy/cuddly/economically-challenged’ for me!

I’ll let you into a little secret.  In one of my previous jobs I used to be a first aider.  That would mean I was sometimes timetabled to cover the first aid office and as a result, I earned the nick-name of Lady Macbeth from my...