Opening an umbrella indoors can still be considered dangerous today but the superstition of bad luck came from the Victorian times.
Umbrellas back then were built with wood, Baleen or metal frames, making them a much more heavy and clumsy mechanism.
The bulky and sharp spokes were accurately far more dangerous as they sprung open like a large wheel of dull knives.
Originating from ancient Egypt, anything shaping a triangle, such as the pyramids were considered sacred.
This was not limited to the triangle shape a ladder makes while leaning against a wall.
Walking through the triangular gap was thought to trap the spirit of the individual within the powerful grasp of the pyramids.
In ancient Greece, analyzing ones reflection in a bowl of water was done to predict their future, Distortion in the reflection was thought to damage the soul.
When mirrors were introduced, the unfixable breaking of a mirror was thought to disrupt a “7 year alternating cycles of health and sickness”
Thus cursing the individual to 7 years of disaster and grief until the soul can heal.
The black cat myth comes from many origins but earliest sources comes from ancient Egypt. Cats were thought to bring luck as well as take luck away.
When King Charles the 1st's lucky pet black cat died, he bemoaned that his luck left with the cat.
The very next day, he was arrested and charged with high treason causing the belief that all black cats were more unlucky than lucky.