How you answer should show self-awareness, as well as your positive attitude towards life. Every setback is a life lesson toward greater success. Describe the situation, the obstacle, and how you overcame it, figuratively or literally. Use examples that showcase your ability to adapt your work style, highlighting your resourcefulness, quick reaction times, and the big-picture logic behind your course of action. Avoid examples that reflect poorly on your performance or reliability.

"There was an opportunity to take part in being one of the first to start up a department abroad. I was excited about the opportunity, but I'd just started a new relationship and invested in that instead. The relationship didn't last, and now, in hindsight, I wished I'd jumped at the chance. It would've furthered my career in leaps and bounds. I'd say that was my biggest regret."