Superstitions

I broke a mirror this morning while getting ready. I accidentally dropped my hand mirror on the tile floor. It pretty much shattered. :( According to superstitions from many years ago, I am now facing 7 years of bad luck!?! Personally, I don't follow this kind of thinking, but I've heard of many people that do. For example, my aunt used to make this X mark across the windshield if she was driving down the road and a black cat ran across. I laughed and thought it was crazy, but just something she'd heard for years and wasn't taking any chances. :D
Do you believe any old wise tales or superstitions like these? Why or why not? Where did the breaking a mirror superstition originate?

I believe in some of them. I don't believe in the one about the mirror because I broke a mirror about two years ago and I haven't really had any bad luck. I kinda believe in the one about the cat. I do mark a x on the window if one runs in front of the car. It originated from different times and different places.