I got asked this question so be prepared. Your response can’t be as bad as mine because I messed up BIG TIME. I said my biggest failure was being a failure to my father. He always wanted me to become a doctor but I chose dentistry bc I thoroughly enjoyed it and see myself making a bigger impact in the field. Something along the lines of chasing my dreams and not trying to please him. This is common in Asian culture but the interviewer could’ve interpreted it as me saying the dental profession is a failure, which wasn’t my intention. I’ll let you know once I get my auto-rejection on dec 1st. Just make it personal and actually a failure. If your biggest failure is having a low gpa, you haven’t lived life lol