BAD LUCK

Johnson's first law of auto repair: Any tool dropped while repairing an automobile will roll under the car to the vehicle's exact geographic center.

Traditional.

Medieval theologians argued that since a ladder leaning against a wall forms a triangle and a triangle is a symbolic reminder of the Holy Trinity, anyone who carelessly blunders through this mystical space is risking divine wrath! Even when that argument lost itself in history's muddle, condemned Englishmen about to be hanged at Tyburn or some other notable place of execution were required to walk under the ladder that stood against the gallows for convenience of the executioner. In those circumstances, you could say the man was certainly in for a spell of very bad luck.

Source Unknown.

For centuries educated and literate persons considered it important to start the day by getting out of bed on the right side. The meaning of the verbal formula, which is now more familiar than the ceremony that produced it, is literal. To get out of bed on the left side was to invite trouble, for the left side (Latin sinister) provided easy access for evil spirits.

Source Unknown.