My question is what are some bad luck superstitions you have read/been told about?
Don't sleep opposite a mirror.
Don't put a hair brush on the table.
If you smash a mirror, bury the pieces in the ground.
http://www.snopes.com had a list of them on their website, which I read ages ago.
EDIT: I thought I would ask only because it was Friday 13th yesterday and I had the shittiest day of my life. EVERYTHING WENT WRONG FOR ME!