I don't know but I dreamt of a high school boy friend! But if he thought about me I'm sure it was a nasty, mean, acidic thought (I broke his heart really bad after I broke up with him I ended up dating his best for a year) So I am hoping it is just one of those "things" that don't mean anything LOL
It would be nice if it was true,they would be thinking about you as well i'm sure.
I'd say it's because you might miss them / think about them =) We mostly dream about the things that keep playing in our minds =)
she is all I dram of, even waking dreams