ive had a couple like the ones you first describe, ive had some such good ones when i wake up im actually reaaaally annoyed that its over haha, cos theyre so real! most of them are random but they dont change surroundings like you describe.
yeh its normal....desire dreams are kinda shit like that.... as for the drastic change of scenery....diffrent aspects of your life are being brought up. try figure which ones relate to which dreams. it would be great if we had a narrator with us in dreamland, telling the story as we hopped along.... ' ooh wainwright, your way too trusting....the bigger the smile, the bigger the arse'
Sometimes I have random dreams similar to yours (people's faces constantly changing, senseless things popping up, going from one situation to the next with no logical transition, ect.), and they feel like a total blur. However, most of my other dreams take place in a coherant and consistent world. And what's more, they feel extremely realistic. I guess everyone dreams differently...