While rinsing beer bottles this morning there arrived in my consciousness a curious lost solecism of my youthful 'hood. I don't know whether this turn of phrase existed in other places, or whether it has ethnic roots, but I've only encountered it in this one (admittedly fertile) linguistic neighborhood, the 19th Ward of Rochester, NY.

The phrase is, "You better be lucky," but used to refer to things that have already happened. "You better be lucky I didn't bust you upside the head," the swell would say to cool his unrealized frustration with the protagonist. "You'd best be lucky I ain't bring my knife today." Later, it would become simply, "You better be lucky. You better be lucky."

How did this get started? Do you have this expression in your neighborhood?