"...you do not have a story until something goes wrong."
This phrase leapt out at me while reading Steven James' article, The 5 Essential Story Ingredients in Writer's Digest.
It's a simple phrase, and yet encompasses all thought processes when writing. It is the taking-off point of a story, the draw card for readers, even if it is only the promise of conflict. You could have the most perfect character (not a Mary-Sue) that readers empathise with, but until something goes wrong, well, the readers will close the book and forget about the well-crafted protagonist. Your plot might be a marvel, straight from A to Z, but unless it takes a detour into 1 to 10, who cares?
It also sneers at regimented structure. Plotters detail conflict while pantsters expect something to go wrong at any time. I remember writing a book where the protagonist avoided conflict right up until the last chapter and even then the antagonist basically did himself in. Fortunately, the computer crashed and it was the only manuscript that couldn't be saved. Unfortunately, I have a hard copy to remind me of that most egregious error. It wallows in the bottom drawer of the filing cabinet as punishment. One day, I might drag it out and re-write it, with a lot more conflict.
In Holly Lisle's excellent Mugging the Muse, she suggest conflict on every page. It can be the standard action or it can be dialogue, but a conflict must be there to keep the reader reading. Sage advice, although I suspect you can stretch that out to every two pages so the reader doesn't exhaust themselves.
Real life is full of twists and turns, the good and the bad, and the unexpected - you story should be, too.