when those dreams happen to me, they are almost always absurdly more random than the other dreams. I've never intentionally got to the lucid stage (if it's even possible) but I find that when you obsess over something to the point of agony, stay up extremely late, and have really funky food, then when you wake up, then go back to sleep, what you were dreaming about 1 out of 5 times will be what ever you obsessed over, and turn lucid. I usually hate it because I get so attached to the dream world that when I am ripped away, (i have to get up for school etc...) I'm depressed all morning.