I wish I knew! I have regular dreams which are so vivid it takes me some time in the mornings to decide if the incidents in my dreams (usually nightmares, to be honest) are, in fact, dreams or reality. I also often dream about something which actually happens the following day. Nothing major usually, but it still freaks me out when it happens. Some time agao, I suffered from Sleep Paralysis, which was extremely disturbing. Until I realised what it was, I thought I was losing my sanity.
And where do the memories of them go, sometimes I wake up completely aware of what I was just dreaming about and make an effort to remember so I can think more about it, and then it just vanishes!
I have very vivid dreams too, this has increased with certain medication that I take although they have always been vivid, just feels like more constant now. I'd have to try and work out if things have happened or not too before now.
I used to have a weird thing of "waking up" believing I was either someone where shouldn't be or that I'd left the hamster cage open, that kind of thing, and would make it downstairs in the case of the hamster or would be feeling round in a panic trying to get out of somewhere different to where I actually was (feeling for the door etc...). Don't seem to have done that for a while though.
I get recurring theme dreams too. One with something chasing me and maybe others. It would usually end with me just getting away then the thing after me would rear up in the rearview mirror, then I'd wake up.
Another common one is that I have an exam but I haven't studied and am panicking about last minute studying and if I will fail. I never tend to get to the exam though. These ones tend to be quite vivid.
When I was in quite a stressful job I used to dream about things I'd forgotten to do, or should have done. It got so bad that as soon as I woke up I used to phone my ansaphone at work and leave myself a message about the dream.
One night, I really freaked my Partner out. Apparently, he was woken up by a strange, denomic voice, and when he looked at me, the sound was coming from my mouth. The thing is, I ALWAYS remember my dreams. I can even remember the recurring dreams I had as a small child. Very strange, but VERY clear, even now. My dreams often run like a tv serial, continuing every time I fall back into a sleep, even when I really don't want them to.
I've always had vivid dreams since I can remember. gness would have appreciated last night's as I was talking to Stephen Fry. Eventually I waved him off, he on the top deck of a bus. Very strange.
I keep a notepad and pen on my bedside table and when I wake up after a dream(whether it be good or bad) I write it all down. It's all sooooo vivid and clear. In the morning, i rarely remember any of it.