Of course, Google didn't answer my questions, people who were working at Google at the time did. (:

As to the specific responses, I'd have to check my old notes, which I don't have handy at the moment. For "tier 1" companies, such as Google, common responses to "What brought you here" and "Why do you stay" are excellent comp, being able to work with many very talented people, and the ability to move around in the org.

I've found the "what keeps you up at night" question has the most diverse responses.

In general, I've been pretty surprised at the amount of apparent honesty I get. It's hard to verify the responses, of course, but any time I get a response that's not completely positive or 'canned' in some way, it seems pretty legit.