So I paid particular attention to her blog post on It's good to be wrong - Or, why my characters use the scientific method. She says:
I especially enjoy it when I've got two or three different points of view, and each of them is wrong about something, and nobody really has it right. It creates such great opportunities for conflict and learning and personal growth, and often makes the story that much more worth reading.
The more complex the real solution is, the more valuable it is for you to break it down into smaller steps. I write pretty complicated puzzles, and I really need to make sure I'm keeping people with me. I need to make sure I'm showing exactly the thought process that leads the characters to the conclusions they draw. That's why this is so valuable for me. That's also why I get so gleeful when I discover a moment where the characters think they have it all put together. Readers will know we're close to the end, and when the characters go, "Aha!" the readers will likely go "Aha!" as well. But there's still something left to learn.
The thing that strikes me is how respectful this is of the intelligence of the reader. Whether a story is specifically a puzzle (mystery, etc.) or not, reading a story -- entering a world which you know nothing about -- is like a mystery. The writer hopefully gives you all the information you need to imagine the world, the characters, the situation... One way is to hand it to you on a plate, omniscently. First of all, that's condescending. And boring. And what do you do when you think differently from that know-it-all narrator? Grinding of teeth, gnashing of jaws, soaring irritation, books thrown across the room...
As writers, we learn to take our readers by the hand, introduce story elements sequentially, and leave room for the readers to interpret, anticipate, guess rightly or wrongly. In other words, to participate in the story. We do this through our point of view characters, and that's why Juliette's approach -- letting her characters be fallible but intelligent -- works so well.