Character Surveys or questionnaires

So many writers do "character surveys" of their main characters to get to know them better and really make them come to live. These surveys for those of you who are not familiar, ask a variety of question such as "What is their favorite color?" or "Do they have a birth mark?" or "What do they consider their greatest weakness to be?"

I have always hated these. I have tried to do them on a number of occasions, but I hated the experience and I never felt like knowing my character's favorite color really made them come to life. Some of the questions I could answer based on what I have planned out of my plot, for example, if my character just wants to make a lot of money so she won't turn out like her white trash mother who she is embarrassed by, then a question like "What is their greatest fear?" could make sense. I could answer that based on relevant information from the book. Someone who simply read my book could figure out that answer.

But the majority of the questions are completely irrelevant to the story I am writing and what my character had for breakfast doesn't seem to "round them out" at all. I am simply making up something, probably the first cereal that comes to mind, since what they had for breakfast simply doesn't tell me much about their character, at least for most people it doesn't. Of course, if someone has a butler preparing him eggs Benedict at six AM then that is relevant, but for your Average Joe, it is probably more indicative of what was in the cupboard or fridge when they got hungry.

HOWEVER, I am going to qualify this by saying that I have never been great at character development. Plots have always been my strong point and I take a plot and run with it. My characters go through harrowing adventures but their actual character seems a little soft or flat. Maybe this is because I am totally an introvert, and would spend my life in a cabin in the mountains by myself if I could. But whatever the reason, I am well aware that this is something I need to improve on in my writing. Twice now I have gotten rejections from agents regarding Finding Innisburg that said "Your premise is intriguing, but I didn't connect with the narrative as strongly as I had hoped." In my interpretation, this is agent-speak for "You have a good plot idea but your characters kind of suck."

So as I go into my yet-unnamed "zombie" novel (I put "zombie" in quotes because Aaron has informed me that I do not understand the concept of zombies, having not watched enough zombie movies, and thus my zombies are not TRUE zombies and I will piss off zombie lovers such as himself if I call them this. However, for lack of a better term, they shall remain "zombies" until further notice.), I want to develop my characters better and thus I have issued myself a challenge:

COMPLETE A FULL CHARACTER SURVEY FOR EACH OF MY EIGHT SUSPECTS AND MY MAIN PROTAGONIST

This will be like pulling teeth for me, but many, many writers who are much more experienced than I am swear by this method and I cannot discredit it without giving it a real, fair try. So I will answer every question no matter how unrelated to the story it is, and see if I "get to know" my characters any more. Wish me luck. I'll need it.

Also, I am interested in knowing if you writers out there use these, and if so, how effective they are for you. FEEDBACK TIME! :-)