The child and grandchild of professionals, I am never sure whether the Irish tradition I learned from my parents came from their parents, or their parents' Irish maids. BUT, as I know that you must pay a friend a penny if they give you a gift with a sharp edge (Otherwise it will cut the friendship.) As I know that if you wish bad luck on someone else it will come back to you three times, as I know that if you put wedding cake under your pillow you will dream of your future mate, so I know that if you kill a spider you will bring on rain.