Back in 2008 a young man called Adam Blair wrote to Pete Docter at Pixar. He was hoping to get a signed photo, and talked about his admiration for Docter's work. Months later, he received this reply.
First off, let me apologize for taking so long to respond to your very kind letter. Things are pretty nuts around here. You had asked for an autographed photo of me; I don't really have anything like that, not being famous. But here is a drawing of me for you.
I'm sure you can see the resemblance.
You are sure right about the importance of a good story in movies. Unfortunately, it's not as easy as it sounds. It takes a lot of work (and rework, and rework and rework) to get it right. And even then quite often we're not 100% pleased.
As John Lasseter likes to say, our films don't get finished, they just get released.
Hope you enjoy "UP" next year!