What is your favorite Demand Generation interview question and the best answer you've heard?

My favorite question to ask is "What is a program/campaign you are proud of and why?" I feel passionate about some of my past campaigns and I want to work with people who are also excited to do what we do. I also get to see if they value. Is it creativity? Is it growth hacking? Also they get share the value of the campaign through numbers and creative story telling. Also a fun perk is maybe walking away with some inspiration for future campaigns! 

I have one question that I love to ask in all of my in-depth interviews: "What is the challenge you are looking for at your next opportunity to help you grow to the next level in your career?"

The best answers are those that sound intentional, thoughtful and deliberate. "I want to grow in my ability to do (x), and through this role, I'll be able to take on challenge (y) to help me get to the next step on my career path to (z)."

One of my favorite demand generation questions is aimed at understanding how individuals approach challenges. Everyone comes prepared with success stories, but I want to know how you handle campaigns that don't go as planned. As someone who values testing and experimentation, I recognize that not all tests yield positive results. How do you learn and grow from campaigns that don't align with your hypothesis?

The question is: Can you share an example of a campaign that didn't go according to your hypothesis, and what did you learn from it?