I love asking people the question ‘what has been your biggest achievement?’. It allows me to find out more about what makes a person tick, what drives them, what they value in life. We don’t just recruit job titles and responsibilities, we recruit people and this question can inform the interviewer of so much.
Some career coaches and recruiters will advise you to always give a professional achievement. I, however, disagree (unless the interviewer specifically asks you to). Some of the best answers I have heard have been personal achievements. Check out the video below for my tips for answering this question.