Most people believe that this is an unlucky day, but not me. I think it all started in France when they found and killed a very skilled Alchemist. This had nothing to do with magic or the black arts. Alchemy was a precursor to chemistry.
"In the Middle Ages. The historical records say that Jacques de Molay Grand Master of the Templars was arrested on October 13th, 1307 AD – a Friday. Eventually he was executed in 1314 AD. Hence, Friday the 13th, is considered to be an unlucky day in Europe." [from Paulo Coelho's blog]
This is why I am not fearful on this day. The Templars did have secret experiments, but only because it was considered heresy to do these experiments. New ideas were considered a danger to the church. It may have been a bad day for Alchemy, but it survived to become what we now know as Chemistry!