That said, what is worse is getting halfway through the book as a reader, and discovering your mental image in no way matches with the character. There's one or two cases where that might be the POINT of the story, but outside of that, I don't like thinking a character has, say, green eyes and curly red hair only to find out they really have straight black hair and brown eyes.
This drives me nuts! If I form an idea of a character in my mind, I find it really hard to change it, and whenever I read a bit that contradicts my personal image of them I find it really annoying.
