What Did You Learn From Your Biggest Professional Failure?

Interviewing is not a slanging match, it's about coming up with something greater than some of the parts. Tell me about your biggest professional failure and what did you learn from it? 'm looking for somebody to be able to admit when they're wrong or when they don't know something' And everybody has their story here - i can tell you about the time that i accidentally dropped ta table in a production data base.