h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

one and two sound like urban legends retold.(my sister knew a guy who's girlfriend's hairdresser...)
three sounds like something reported in the daily sun news.
four sounds like the one told late at night over a case of beer, or another urban legend.
all four could be ghost stories, or a load of doodoo you just made up.

BTW experiences of dreams coming true are common, but #4 was melodramatic enough to have been made up. about 10 years ago I had a dream that came true. being a sceptic I tried to discount it, but there were too many facts that fit; 1) I warned the girl involved a full 24 hours before the incident happened, 2) I had no idea she was going to take a road trip when I warned her, and she denied planning one(then got an emergency call that made it necessary)
3) I predicted a brake failure that, when investigated, could have happened; she had a pinhole leak in her brakeline, and repaired it that a.m., before she got the call to leave town,and I saw the discarded brake line, 4) I dreamed the exact location and circumstances of the potential accident, and 48 hours later she confirmed it. a certain underpass, a sudden rainshower obscuring vision, a drunken driver on the wrong side of the highway.
I often wondered if she hadn't made the whole thing up, verifying the dream to pull my leg, but when she did she sincerely thanked me and looked scared, and then avoided the issue, (and me) for 2 weeks, like it creeped her out. she acted like it was real for her, so either it happened or she was a really good actress. probably the latter.

Thanks for the reply. You were more or less accurate (except no.1 was *supposed* to be true).
Personally, I blame hysteria, hallucination and whisper-mongering, but I could be wrong.