What does it mean to dream of your grandmother?

It's probably you're just having subcontious thoughts. Dreams are like a movie; they play back events and things you've been thinking about subcontiously. This means, that there is like a net at the back of your brain that catches all of the subcontious thoughts you think in a day, and at night, when you get into your R.E.M. stage of sleep, your brain plays back what you've been thinking about. Here's the tricky part; subcontious thoughts are thought, well, subcontiously, so while one part of your brain is concentrated on something, like talking, or hanging with your friends, the other part is thinking about other things, and you dont even notice it. The only time you notice these thoughts is when you're dreaming. Maybe your grandma is ill, and subconciously, you're worried about her, so you have dreams that she dies. Who knows? ONLY you... hope I helped:)