Not directly on topic, but close enough - I've only ever had one nightmare; I was seven, and the dream was that the family was in the house we were actually living in, in an expatriate community in Nigeria. Someone was in the house, and killing everyone, one at a time, until it was just myself and my father, hiding behind the curtain together.
Now - a neighbour of ours had just been broken into and murdered, so it's not too difficult to see where this dream originated from, but that isn't the point -
I woke up, and couldn't get back to sleep, seeing the same image of the knife coming around the corner of the wall, through the curtain fabric (as I see it now, after all this time)... but eventually I did..
... and my mind played out a cartoon. Literally - "Hagar the Viking" - complete with a logo and credits.. a cute cartoon Viking that my father and I had a snowball fight with, laughing and having fun, then the credits rolled, and I drifted into a deeper sleep. Nearly fifty years ago now, but I can remember the entire thing.
Never had a nightmare since. All my ...interesting... dreams are in the form of thrillers; they can be scary at times, but fun scary.