According to Google, Friday the 13th is a widely recognized Western superstition symbolizing bad luck, primarily rooted in Christian tradition (13 guests at the Last Supper, Crucifixion on a Friday) and Norse mythology. It is believed to bring misfortune, leading to "triskaidekaphobia" (fear of the number 13). 

Key Origins and Beliefs:

    Biblical/Christian Roots: The 13th guest at the Last Supper was Judas, who betrayed Jesus, followed by Jesus's crucifixion on a Friday.

    Norse Mythology: Loki, the trickster god, appeared as the 13th guest at a Valhalla banquet, bringing chaos.

    Knights Templar: On Friday, October 13, 1307, King Philip IV of France ordered the arrest and torture of thousands of Knights Templar, cementing the date's negative reputation.

    Cultural Significance: In many cultures, 12 is seen as a complete number (12 months, 12 zodiac signs), making 13 an unsettling disruption.

    Modern Interpretations: While largely considered a superstition, some studies have inaccurately suggested increased accident rates, while others find people are simply more cautious. The day is also sometimes viewed by modern practitioners as a time for, or, to embrace the divine feminine and transformation.