Know what one of the worst type of nightmares are <img src="/ubbthreads/images/graemlins/question.gif" alt="" />
I reckon the worst ones are when you wake up and realise that it could be real. I had one dream a while ago that did this to me.
I was visiting a friend who had just moved into a new appartment. I had a kid with me who I was looking after. We stayed the night. The next morning I woke and was chatting with everyone. I spoke with the kid who told me how he killed one of the boys at school who had been bullying him. I could see the bully's corpse in the next room. The kid acted like this was the most natural of things, killing someone you didn't like.
I woke up feeling rather disturbed by this dream. Not only was the content disturbing, but I woke up agreeing with the kid. At that moment, murder was acceptable.