Colonel Midnight wrote:
If the person isn't ready for it (and it usually gets them off guard, as one usually wants to praise yourself in an interview, not talk about problems you've had)... It'll show if they can think "on their feet", as well as adapt and overcome obstacles.
What does thinking on your feet and coming up with elaborate stories on the spot have to do with performing your job? Unless you're interviewing someone to be a talk show host, you're testing a skill that's completely irrelevant for the position at hand.
It's not about storytelling but an interviewer usually wants to see how a candidate handles himself under pressure and asking such loaded questions is one way to do it. If the person gets a halfway decent answer together he passes showing he'll not freeze up when it gets hectic and chaotic at the job (which at some point will happen).. if he passes with flying colors, i.e. stays calm, gets together well worded sentences and appears to be truthful and what he says makes sense then he scores extra bonus points.
Once you get to an interview at all, i.e. passed basic requirements such as grades, work experience and other requirements interviewers want to get to know the person behind the diplomas, certificates and numbers and they do like to put people outside their comfort zone because it's then that most people show their true colors.