Catherine and her Fate is a story that barely fleshes out its central idea: do you want to be happy in early life if you know you'll be sad later? Or would you rather get the sadness out of the way now if you know for sure that means you'll be happy later? Basically, if dinner is a meal that lasts your whole life, do you start with the pudding and then go on to the dubious vegetable mash, or is vegetable mash first and pudding last?
Catherine says she'll start with the sorrow, please. That stuck with me all through childhood: the idea that we had a choice about what we waded through. Of course, in the fairy tale, Catherine knows for certain that her happier days are coming if she slogs through the sorrow first. The story is only instructive because Catherine lives to claim her reward. As an adult, I know that's not always the case. Sometimes it's worthwhile to take your joy first in a life where there are no guarantees. But as a kid, I think I needed Catherine's story.
Note: I couldn't remember anything about this story, which has always stuck with me, but a Google search for "fairy offers a girl a choice about whether she'll be happy in youth or in old age" brought it right up. I love living in the modern age. There are versions online from Thomas Crane and from Andrew Lang's Pink Fairy Book.