When a lot of people see the number 666, they immediately get scared, most likely because they associate it with the evil entity that is mentioned in the bible. But what they don't seem to know is that the number itself can't hurt you.
At times, I've seen items in grocery stores that had a $6.66 price tag on it, and I figured that most shoppers would probably not buy that particular item due to it having those numbers on it.
One time when I had grabbed a few items in a store then went to check out, my total came to $6.66. When the cashier saw the total, she gasped a little. And I smiled, because I knew why she seemed to be a little scared of seeing that number.
