I always find it amusing when a youngster comes here & tells us they are mature straight after going off on one...
Anyway regarding the Q. I agree with divegirl & ~Floella~.
Dreams are incredibly short. You know those epic dreams you have which seem to go on for hours, and are generally the last thing you dream? they are only a few seconds to minutes long. You actually dream more than one dream per night too, but it is only the last dream you remember.
I remember dreaming Princess Diana died the night it actually happened. I was asleep on the sofa with the TV on...