Yes, I think sometimes choices you make in dreams can have real impact. I had a dream once where I was on the phone with some tech support or something and I got frustrated--I think he got a little edgy--and I was right at the brink of either diffusing the situation or telling him off.. and I made the wrong choice. I told him off. I told my friend about it and she said 'what a fucked up dream. I wonder why you had it.' then she said sorry later and revealed that the reason she said that is that she had a feeling recently that she didn't have such a "blingin' vehicle" anymore and that it affected not only her but a number of people (I assume people I was connected to, directly or indirectly).

I think the dream was given to me so that I could have done some good, the powers that be made a bet on me making the right decision, and I failed.