Our family is aflicted with a curse. Its a rather common curse actually. And its not very serious really.
What it is, is whenever we step out into bright sunlight we sneeze three times.
What? You say it isn't a curse? Well it has all the characteristics of a curse. It is certainly undesirable and it is a family curse because many members of our family are aflicted.
What? You're still arguing? It's not a curse, its an inherited DNA defect, common to many many people not just our family. Well you're right of course but who's to say the DNA wasn't damaged in an ancestor a long time ago by a curse. Maybe the curse was delivered in a poison potion.
So if you notice someone sneeze three times when they step outside you will now know, they are aflicted by the same family curse. It must have been a very popular potion amoungst cursers.