My one interview question (I have a series of related but only go down them selectively) is “tell me the one thing you’ve done that made you the proudest of what you have achieved or the happiest with what you were doing, don’t worry whether it was the most impactful or important from an outsider’s perspective”. I am trying to give people the chance to show me the best they have, not a competition for me to prove myself I am better somehow. You will be surprised how many interesting discussions and learning opportunities I got out of this question. Everyone who has peered interviewed with me ends up using it in their future interviews.