I guess some people think Friday the 13th is unlucky, but I've never had any major complaints.
This January's was a little stressful, but that had to do with rushing out the door to catch a train, not actual bad luck... And I actually remember this one time when I was in middle school (can't remember what year) and I had a math test on a Friday the 13th. The potential for bad luck was ALL there, especially considering I'd even seen a black cat out the window before I left the apartment that morning! There was no bad luck, though. I got through the day just fine and aced my test!
I've loved Fridays the 13th ever since! : )
(While we're at it, I also love black cats. I grew up watching Sailor Moon and Luna was one of my favourite characters!) : )