Christian is an absolute control freak, and Anastasia resists him at every turn. It's such a tug and pull story that I found it hard to put down. He has definite control issues, and she's the woman to tame him. I love compelling stories with this type of conflict. The writing can be horrid, but if there is a tug and pull between the characters, where they are resisting this attraction with everything they have, I have to keep reading.
Another example of this type of story is Julie James, Practice Makes Perfect. It's the story of two lawyers vying for the same position in the firm and their attraction to one another. I couldn't sleep until I knew how that book was going to end.