Once a wedding ring has been placed on the finger, it is considered bad luck to remove it.
117
If one walks underneath an open ladder it is said to bring bad luck. Sometimes it is said that this can be undone by immediately walking backwards back underneath the ladder.
105
Placing a hat on the bed is, apparently, bad luck. (South Carolina)
9
It's bad luck to leave a house through a different door than the one used to come into it.
143
Some motorcycle enthusiasts hang a biker's bell from a portion of their bike to protect themselves from evil road spirits.
64
Opening an umbrella indoors is said to result in 21 days of bad luck. Some traditions hold that it is only bad luck if the umbrella is placed over the head of someone while indoors.
75
At times, a horseshoe may be found above doorways. When positioned like a regular 'U' it supposedly collects luck. However, when it is positioned like an upside-down 'U' the luck supposedly drains.
78
Pirates believed that piercing the ears with such precious metals as silver and gold improved one's eyesight.
131