Take a story's temperature by studying its tone. Is it hopeful? Cynical? Snarky? Playful?
In these tales, stuff just kind of happens, and the narrative voice usually doesn't linger on the events. For instance, when Gretel pushes the witch into the oven, we're told: "The witch began to howl dreadfully, but Gretel ran away, and the godless witch was miserably burned to death" (58). A human being was just incinerated and we only get a one-sentence description of it. No remorse on Gretel's part either.
So yeah. Stuff: it happens. Then more stuff happens. It's a little more exciting than See Jane Run when Jane is running away from a wicked stepmother or incestuous father, but same idea.