Every writing tutorial I've happened upon asserts that complex characters are intrinsically better than two-dimensional, flat characters. However, could it be that mainstream readers think otherwise? For example, a surprisingly high number of best-sellers have simplistic characters. Harry Potter is chock-full of two-dimensional characters (except for Snape, but he does not make the book in and of himself, and his main appeal seems to be to lovelorn teenage girls). I can't think of any characters in the Star Wars prequel trilogy and classic trilogy that are particularly complex, and the books based on the films are popular. So are the characters. Eragon is a popular series full of two-dimensional characters. Twilight has characters two-dimensional enough to be on par with children's stories like Mary Poppins. Perhaps most people have enough of gray areas in real life and don't want to be confronted with more when relaxing with a book? In other words, maybe having everything in black-and-white (the good guy and the bad guy) is more entertaining after all? Please comment.