People without proven track records of initiative and ambition will likely become a drain, even the really smart, talented ones. They'll ask what's next instead of telling me what's next, or worse, they'll do nothing until given instruction. This isn't how it works at our seven-person startup Hinge, which is a dating app for young professionals that introduces users to their friends' single friends.
I always ask, "Give me an example of a time you failed." It reveals the two most important things: Humility and ambition. Some interviewees can't think of anything, or they come up with a trite example like a careless mistake. Others describe being part of a substantive failure, but mostly blame it on circumstance or others. This tells me they are ambitious but not humble. Sometimes a candidate gives a soul-searching account of failure at some trivial task. This tells me they are humble but not ambitious.
Then there are the ones who talk about attempting to do something great, but failing because of a mistake they made personally. They say what they learned from it, and how they applied that lesson in the future. These are the people I hire.