I think it depends on the company you're interviewing at. If you're interviewing at Amazon, you better have some cases you've prepared where things didn't go a

I think it depends on the company you're interviewing at. If you're interviewing at Amazon, you better have some cases you've prepared where things didn't go according to plan, and where you learned something from that. You had better be willing to stand up and say "I don't know", but you should also quickly follow that with "I will find out and get you the answers within X days".