Chaim Yankel always wanted to be an engineer - he even managed to graduate from engineering school, albeit nowhere near the top of the class. Upon graduation he applied for a job in the City that required its applicants to take a test and he wrote the test along with a classmate of his named Brent Buchanan who finished at the top of the class.
Upon completion of the test, both Chaim Yankel and Brent had missed only one of the questions.
The manager went to Chaim Yankel and said, "Thank you for your interest, but we've decided to give the Brent the job."
Chaim Yankel said, "And why would you be doing that? We both got nine questions correct. What makes him any different than me?"
"We have made our decision not on the correct answers, but on the question you missed," replied the manager.
"And just how would one incorrect answer be better than the other?" Chaim Yankel asked.
The manager said, "It's simple. Brent answered 'I don't know' to question number 5. You put down 'Neither do I.'"