sometimes in dreams I wish the worst to happen

Maybe I should choose another place for this theme ?
Well no! It's perfect here.. let me explain...

It is so weird how when in real I only wish the best to everyone, the best to me, but when I dream I imagine so many bad things and it seems I enjoy a lot.
One of them is the sex.. how I want it and how I dream it... Believe me there's a very BIG difference but still in that dream I seem to enjoy a lot...
I wonder why ?