I used to dream a lot about my father just after he had died. I would see him in my dream as if it were a normal thing, doing all the same things he did in life, like he was still alive though I felt that there was something odd. I think most people if not all dream about people that had died and were close to. When I dream about my father I don't want to wake up. Maybe sub-consciously they are on your mind or represent something that is missing and appearing in your dreams. You don't have to be thinking of them that day or even week for them to come into your dreams. For the most part all dreams are things that are lying in your sub-conscious locked away when you are awake and then free to manifest themselves as you sleep. Everybody always dreams while asleep, if you wake up thinking you didn't dream it is only because you forgot it. I personally like all my dreams, even nightmares but that's for other reasons I won't get into