I'm currently reading a book I was given at a conference last year. The story has been okay, certainly different but not necessarily in a good way. The heroine bothers me. She's an inconsistent bitch. Sorry. No other way to put it.
When I write dialog and scenes, I'm constantly saying to myself, would this type of personality/person say or do this? It certainly helps with my plot and what my characters decide to do next. I've certainly learned not to force them to do or act a certain way just to get from point A to point B. Anytime I have, a little voice in the back of my head tells me something is wrong. And I've learned to listen to that nagging brat.
Plus I like to think though my characters may not have the most redeeming characteristics or conduct themselves in the best of light at the beginning, they're not mean or hateful, more like flawed. I can guarantee you'll see a good side to them before you've read the first third, if not quarter, of the book.
Then on the other hand, I rarely tolerate goody-two-shoes heroes or heroines in the books I read. You know the one who is always trying to do the right thing but others get in her or his way. Boring!
One of my favorite type of characters is the person who appears good and isn't or appears bad but isn't. Yeah. Those are the ones I love peeling back the layers and letting the reader see their growth, the true person underneath, even the bad guys.