Had two pair interviews to work through coding and problem solving steps. First one was ok, person was interviewing was professional and so. Second one the guy was a weirdo as hell. Because i was not smiling while I was thinking in the problem and how to solve he told "You are too serious. It seems you are under stress". What in fact one is if you are trying to do a interview and thinking in solving a problem. Because my 'faces' at the interview he sound to be uncomfortable and gave me NO feedback at all, even after i had explicitly asked him for . So, what is the point in not giving a feedback or even giving a NO, for someone just because his faces under an interview? Without a proper feedback one need to use a crystal ball to get _ALL_ the info to get better and improve. I would expect more professional approach for a big company, but it sounds it is about teenagers playing and get fun.