(or "The Ever-Lovin' Blue-Eyed Thing")
It's the subject of a lot of good-natured debate among comics fans and creators (and a lot of not-so-good-natured debate as well); how much of the credit should Stan Lee get for the Fantastic Four and how much should go to Jack Kirby?
Myself, I beg the question. Comics is an inherently collaborative medium, and to assign credit to either gentleman neglects the contribution of the other. Kirby did his best work with Stan Lee, and Lee did his best work with Jack Kirby. (Although you could make an argument for Steve Ditko, as well.) But there's one area you can definitively give credit to Stan Lee for, and it happens to be the area that we're looking at this week, and the Fantastic Four happens to be the best example of it, so let's take a moment and look at dialogue.
You don't normally think about dialogue as something that opens up storytelling opportunities (which is, after all, the definition of a storytelling engine--an element of the status quo that opens up storytelling opportunities.) But go back and look at the classic Lee/Kirby Fantastic Four. The team dynamic that Lee and Kirby set up provided tons of stories; each team member had a strong personality that caused them to go out and do things that moved the story along. In turn, each strong personality came out of the dialogue that Stan Lee wrote in after seeing Kirby's art; as Kirby, in turn, worked on the characters after reading their dialogue, he found himself able to flesh out the characters' actions and devote more of the story to them. Which, in turn, helped Lee define them more...
Obviously, this works better with a concrete example, and the idol of millions, Benjamin J. Grimm, provides the best case. In early issues, the Thing is just a "surly" character, no different from Rocky in 'Challengers of the Unknown' or the Hulk. But within the first twenty issues, Lee begins to give him a distinct flourish to his dialogue, a mocking self-aggrandizement that helps to counterpoint his brutish appearance. His dialogue with the Human Torch becomes less sniping and more banter, as the Torch's own speech becomes more distinct.
As Kirby takes note of this change, you start to see more scenes with the Thing and the Torch simply interacting, trading barbs and sparring in what has become a trademark of the Fantastic Four to this day. Even in this microcosmic level of filling pages instead of issues, adding scenes instead of storylines, the dialogue defines the characters and the characters generate the stories.
The Marvel Age of Comics, it could be argued, was built on the back of its characters; characters who had personalities, who went out looking for stories instead of waiting for stories to find them. And those characters came, in no small part, out of Stan Lee's scripting; even now, you can tell without needing the pictures whether a line of dialogue came from Ben Grimm, Peter Parker, or the Mighty Thor. That kind of scripting helps both sides of the collaboration.