Are your characters real?

I caught a quick interview by Jill Shalvis online and I was struck by something she said: she basically said that (yes, I'm paraphrasing here) she thought about what would be rock bottom for her and then let her hit it, knowing the character would have to climb her way back. That journey right there is what will show us (not tell) who the character is at the core. That got me thinking: do I know who my characters are at the core? What makes them hurt? Laugh? Cry? Rage? I have plot points, relationships, settings but do I know who these people really are? You need to know if your characters are going to be real. Given that you are inside their heads and making their decisions and that those decisions tell us who the audience is connecting with, you want to make sure you know the people you create very well. What makes them tick? How would they respond to a specific situation? I had to seriously contemplate such questions after I saw the interview with Jill Shalvis. I found myself thinking, "What's rock bottom for this character?" It truly forced me to look at the person I was trying to create out of words. Then today, I was reading Caitlin Rantala's twitter feed (if you don't follow her, you're missing out cause she's awesome)  and she said she almost emailed one of her characters. I thought, "That". Your characters need to be so real that when you're remembering a conversation that's been had, it takes you a minute to realize the conversation was fictional between fictional charcters. But it, they, were so real that you momentarily forgot. So I developed a list of questions for my characters and took a break from my work in progress until I could answer all the questions. I'll share what questions I used in hopes that maybe you'll tell me how you make your characters real. The WIP that I developed these for is quite dark but it was a good starting point. I don't know if I would apply the exact same questions for every WIP but if you can't answer them, maybe your characters need to be fleshed out a bit more.

Ten Questions to ask your Main Characters

1.      What’s their biggest fear?

2.      What is their biggest attribute?

3.      How would they describe the lowest moment of their life?

4.      Who makes them happy?

5.      What are they proud of?

6.      What do they see as their biggest flaw?

7.      What do the supporting characters see as their biggest flaw?

8.      Give three physical adjectives to describe them?

9.      What are three emotional adjectives to describe them?

10.   What do they secretly wish for?

Now maybe your book isn't about their secret wishes but that's not the point. The point is to know your character like you know yourself. Knowing your characters is what is going to allow your audience to know them and if they know them, they'll care for them, and if they care for them, they'll fall into the book and the world that you created. Which is definitely the point.
What do you use for character development?