Well, without more context, it's hard to define the specific 'you gonna cry christmas story'. Maybe it's a story where a poor child experiences a magical Christmas and the kindness of strangers, which is so moving that it brings tears. It might show the true spirit of Christmas and how it can change lives.
If it's a self - made or less - known 'you gonna cry christmas story', it might have unique elements. For example, it could be centered around an old Christmas tradition in a small town that was almost lost, and the efforts to revive it. This could involve the emotions of the older generation seeing it come back and the younger generation learning about their heritage, which could be a very emotional and potentially tear - inducing story.
It's kind of a warning or cautionary phrase. Maybe someone is saying that doing a certain thing during Christmas could lead to an accident where you hurt your eye.
Once upon a time on Christmas Eve, a little orphan girl was sitting alone in the cold alley. She had no family and no presents. She started to cry softly as she watched the happy families going into warm houses. But then, a kind old lady noticed her. The old lady took her in, gave her a warm meal and a small present. It was a simple doll, but for the girl, it was the most precious thing. That Christmas became the most memorable one for her.