Nothing has ever happened to me on the thirteenth, and I honestly believe it is all superstition and complete bogus. I don't even know why they 'cursed' Friday, the thirteenth anyway.
But I also believe that [might be contradicting myself, here] that those who DO believe in Friday, the 13th always experience something. Not because it is actually cursed and whatnot.. but because their minds make it up. It's possible.