Ok , so who are we going to invite to our dinner party ?   Well , we have the Thompsons , the Greens , and the Anderson , about twelve people total .   Don't forget my friend Andy from the office . He has nothing to do on Friday , so I invited him over .   But that makes thirteen people ! We can't have thirteen people for dinner on Friday !   Why can't we ?   It's an old superstition . If we have thirteen people at the table , then it means bad luck . Can Andy bring a date ?   I'm not sure . He just broke up with his girlfriend recently , and I don't think he's in the mood to start again so soon .   But we can't have thirteen for dinner !   I think you're making a mountain out of a molehill . It's only a superstition . It really doesn't mean anything .   Absolutely not ! I refuse to have thirteen people for dinner on Friday !   Ok , ok . I'll ask my sister to come . That way we'll have fourteen for dinner . 