I don't believe in a lot of stuff, but I do believe in dreams. I guess it's because the Bible shows that God talked to people or showed them visions...so since I have a Biblical reference then I'm ok with that. (Thinking specifically of Joseph while a prisoner in Egypt, or Joseph and Mary leaving town after the magi visited them, etc).
I've had dreams that stick with me, and I know to pay attention to that dream, and I'll recognize it in real life soon after. Most of my dreams are "teaching dreams" though. A couple were life changing (in a good way) because I learned something very important. My mom did that too---A less "personal" one: she was terrible at PE in school, always suffered the shame of being picked last, etc. They were having a class baseball game and she seriously dreaded it. She prayed that she could miss school, or learn how to play, because she didn't want to be humiliated. She went to sleep and was at bat in her dream, and saw the pitcher release the ball, the ball go very slowly so that she could see the spin, see when to swing, the connection b/w bat and ball, and even the follow through, over and over. She hit a homerun the next day. Teaching dreams are good.
I had a teacher that had us journal our dreams as a sort of diary of where we are and what we're thinking or dealing with, so I did. As a kid, I had a dream that dad was cheating on mom (she had NO idea, I have no clue why I dreamed that), but I remember being really mad at him and throwing oranges at him. Life changed a lot and we moved. I woke up pretty upset. I didn't tell anyone, I just thought it was a bad dream. 2 years later, he left us for his secretary (pathetically cliche!) and I threw my duffle bag at him as I was leaving for senior trip (the morning after he told us!) and oranges fell out of the bag. One time, I dreamed we went to some guy's house after partying one night (nothing new at that time) and my friend got raped. Sheesh! What a crappy dream! Well, I don't know, some time went by, and we went to some guy's apartment and I felt myself passing out. I think I was asleep and my friend was shaking me awake to say we should get going. Conventional wisdom says no, we've been drinking, and I don't feel like it anyway....but then there was like a half second flashback to that dream and I jumped up to my feet wide awake, sober, and we walked right to the car and didn't stop for anything. We drove in silence for a couple minutes, and my friend said one of the guys was trying to mess with her and she had gotten real scared. There's been a few things like that.
And of course, the grandma dreams: there's been a few of those in nearly 10 years. Grandma was one of my heroes and I guess my subconscious views her as my moral compass; I say this because my religious beliefs don't allow me to think it's "really" her...but I was close to her and she still plays her role in my heart and mind. So, when I am just flat wrong (not often, haha), even on something that doesn't SEEM important, my dream is my grandma setting me straight.
There have been some serious ones my husband has gotten too: once he woke me up when we were pregnant with our first child; it was time to go get a sonogram together. I was trying to wake up but feeling lazy, and he told me he had a bad dream that we were in a traffic accident. I was like ok. But he said NO, wake up NOW, pray NOW, it's serious. I woke up and we prayed for protection. 30 minutes later we're on the interstate and it just goes from 60 to a dead stop suddenly, as we were coming over a hill. We had to slam on our breaks to not hit the cars in front of us, couldn't swerve into the other lanes because other people had already done that to avoid whatever was ahead of us, and there was a big concrete truck barreling down on us, and we were trapped with nowhere to go. We tensed up and watched it through the mirror, and it suddenly just "slid" to the side and there was a hole in the traffic right there for it. He missed us by inches, and it wasn't like a turn, but a slide sideways instead of diagonally forward/right. Another time, he dreamed big block numbers. I can't remember the numbers, but all he saw was a black screen with those numbers real big in white, and he knew it was important, but not sure what they were. When he saw the market at those numbers, he moved our money and it did turn out to be the high point right before it went down real fast. We've since readjusted everything, but we were able to miss that crash because of that dream. One of our friends did the same thing on the same day because he just "felt" to, but we didn't know that until months later.