I remember applying for a job with Canon Copiers back in the early 80's. I was greeted by a woman who looked at my resume and education. She seemed impressed with what I had and gave me every indication that she was going to give me the job.
Problem was some district manager ( chinese guy) was there checking on things and wanted to see me. I sat down and did the greetings and such and then out of the blue he threw a series of complex mathematical questions at me. He caught of guard and I was unable to give him the answers he wanted.
He asked me why I couldn't answer the math questions. I said I was caught off guard to start and that I have trouble doing those complex type of equations in my head. I also said I could do this if I had a calculator. He gave me this look of wtf and said you are on no use to me
I'm leaving the building when the same woman who interviewed me said it was bad luck that he was here today. Any other day she said and she would have hired me.