Authors create characters sometimes based on people they've known and sometimes out of their imagination. During the course of the story the reader learns not only what they look like, but some of their background, likes, dislikes and motivations. It drives me crazy when I get to the end of the book and I have to ask myself why that character chose an illogical course of action.
I just finished reading a romantic suspense by a popular author. One of the main characters was a totally selfish woman who slept with her sister's boyfriend,stole other women's husbands and was so totally focused on her career as TV personality that she staged a kidnapping just to up her ratings. When another women is killed, her only concern is how it will affect her. Okay, I buy all that. Then somewhere near the end the author throws in that years ago the woman became pregnant, went somewhere to have the baby and gave it away because a child would be a detriment to her career. I have to ask myself, why didn't she have an abortion? It's not like this woman valued life. Someone obsessed with her physical ability to attract men wouldn't go through nine months of pregnancy. The author gives us no reason, no explanation for this.
The only thing I can come up with is that the author threw it in to make the story go where she wanted. It isn't the first time I've noticed an author sacrifice the believability of a character for the plot line. Isn't this something the story editor should catch?
Authors, if you have one of your characters do something alien to the motivations you've created, at least give us a plausible reason, some temporary change of heart or possibly a fragment of back story to explain their actions.