What's the one that got away? The one you got to the last stage of interviews for, but then got the rejection. How do you think your life would be different if you'd got it?
More broadly speaking, what was your initial plan of what you were going to do with your life growing up? Did you change, or were there other reasons you never ended up doing what you thought you were supposed to be doing? Would you be a prime candidate for Sam Beckett to Quantum Leap into?
Even broader again, what would be the best job in the world ever?