"Tell me about a time you've failed" is a trick question. Interviewers ask it to gain a sense of your ego, your ability to handle adversity, and how you rebound. But it is a trick question. Let me explain.
During coaching sessions, I often ask my clients, "what does X mean to you?" or "what does Y look like to you"? Some variation on that. Words have specific definitions and, since language is fluid, we have the ability to express ourselves in whatever manner we want and need to characterize our experiences. Recently, I asked a client what success looks like, and they asked back "didn't we already cover this last time"? Well... yes. But they defined success about a specific Thing and this was another Thing. The markers for one don't necessarily describe the other.
Much like I ask clients to clarify their meaning of success or happiness or whatever, my sense of failure is not your sense of failure. How I quantify or qualify failure is dependent on many variables. And there's the trick to the question: what do you mean by fail?
We're taught that failure is something to be afraid of, to stay away from. If we want to innovate, if we want to drive our industries, and if we want to supercharge our lives, we have to get over failure-as-bad real quick. (Forbes, Medium, The Atlantic, HBR, and many, many other business publications agree.) Think of failure as a series of iterations to get something closer to "right". Within those iterations, explore with resilience, humility, and an open heart and mind. With failure comes risks, and with risks come opportunities. Failing is getting out of your own way to be able to see what's next. Failing builds character and focuses the journey. Don't be shy: fail hard.
The next time you're invited to tell someone about a time you failed, chin up, deep breath. Don't dwell on the failure; regale them with risk and tell them what you learned.