I read an interesting post this morning (while trundling around the net, procrastinating about marking assignments) that talked about "liking" and enjoying your characters, especially your viewpoint/main character, rather than being "in love" with them. The writer said she thought being in love with your character can blind you to how you are writing about them - you might be having a wonderful time, getting them to do all sorts of enjoyable things in the story, but actually end up writing drivel. In other words, fun for you but what about the poor reader?
It's an interesting thought. How often are we told we must love our main character, know them inside out, want to tell their story, etc etc. Writers talk about how the characters "just took over the story and I had no control over them", and that certainly does happen, but I do believe your subconscious comes into play at that point. Your own suspension of disbelief (i.e. these are not real people) allows you to fully engage in what is possible for them. If you hold the characters at arms-length and manipulate them on the page, the "taking over" is not possible.
For me, the idea that being in love with your character can blind you to bad writing rings true. When I know a character well, but am not in love with them, I can see their flaws as well as their good points. I also like writing in order to find out more about them. Sometimes this happens in the novel, but often it happens in the extra writing. If I feel I'm not getting to grips with a character well enough, I'll free write about them, ask them questions, let them answer in their own voice. Free writing unlocks the subconscious element of character creation far better than the actual novel does, because you are not constrained by story. And it's the subconscious part that reveals things about the character that you didn't know you knew.
OK, so all this subconscious stuff sounds weird, or at least a bit suspicious. Try it for yourself. Free write a scene where you sit behind a desk and your character enters the room and sits on the other side. Ask them questions, and then free write their answers. The key is in the free writing - you do it fast, without stopping, without editing, and you keep going for at least twenty minutes. If you've never tried free writing before, make sure you stick to the rules. If you want to know more about it, Wild Mind by Natalie Goldberg is a great book.