I had a candidate once. They were having trouble getting the message body on a 400 level error during the technical interview. They had chosen to solve it in Java. I'm not a Java developer (and I let the candidate know ahead of time and that I could only help with naive suggestions). Their exception message was pretty clear. After they prodded around for a bit getting nowhere, I pointed out the exception message. He ignored my suggestions multiple times (multiple angles of "your exception says blah"). After the interview, I took his solution and fixed it per the exception message. Boom. Worked. After the interview, his feedback to our recruiter was that it was obvious I did not know Java. Some people are bad at reading and listening :(. Also, this was a former Googler. It helped shatter an (unconscious?) bias that somehow Googlers were a breed above the rest.