"When you present your readers with already-arrived-at conclusions about your characters, you leave your readers with nothing to do, and passive readers are at best unengaged and at worst bored. You need to let your readers take an active role in the writer-reader partnership to draw them into your story." (Self-Editing for Fiction Writers, p30)

Ross's Take: One thing that really made an impact on me early in my training with TED was the importance of leaving some things to readers' imaginations.

My mother Renni often refers to the guiding principle here  as 'co-creation', and it basically  boils down to leaving some empty space in what you convey  about your characters, so readers can come to our own conclusions and bring something of our own perspective to the table.  That, too, is part of genuine engagement. And nothing interferes with this more than when an author describes everything down to the last detail.

While this principle certainly applies to personality, temperament, disposition or what have  you, it also applies to physical description. Have you ever seen a movie based on a book and had to deal with a lead character who looks nothing like the character you envisioned when you read the book? It can actually be pretty jarring!

There are all sorts of good reasons that a certain amount of restraint is  valuable when it comes to characterization. But to my thinking the best argument for this lies in what makes the experience of a book so unique and valuable versus that of a movie, play, tv show or whatever. If nothing else, books stimulate the imagination an a way that these other vehicles for story cannot. So why not leave something to it and enjoy the heightened sense of interaction and engagement between the book and its readers.