People typically remember their dreams when they wake up in the middle of one, and usually then the REM sleep stage. I remember some guy studying this, got his

People typically remember their dreams when they wake up in the middle of one, and usually then the REM sleep stage. I remember some guy studying this, got his assistant to wake him during REM and found the dreams were pretty vivid when this happened. Maybe you're just enjoying a sound sleep and waking at the "right" time.