It’s no superstition. Ugly people have traditionally brought good luck to the rest of the population (they’re good for something after all.) Remember, it is good luck to touch a hunchback’s back, or to see more than one blind man in one day. There is also something about encountering nuns and gypsies, the details escape me.
We have a friend who is wildly superstitious about Friday the 13th.
He also knows the one about “rubbing a red head for luck”.
If I was unfortunate enough that we were riding with him on one of those ‘awful days’, I came home with a sore scalp because every time we came to a stop light or got off the bikes, he’d rub my head like crazy.