None of us should, because we’re always learning and always growing, or at least we should be: That’s a sign of humility, curiosity, openness. Show me someone who believes and says the exact same things about the world that she did 20 or 10 or even five years ago and I’ll show you someone who hasn’t been properly living in it.

Questions can be crystallizing for candidates and voters, and some politicians have had their finest moments answering tough questions on their feet.