3. You are interviewed in a noisy and crowded room
This is a sign of an inexperienced interviewer who may be trying to suggest that he is so important that he cannot leave the centre of his powerhouse. In most cases, you will just have to put up with it and concentrate hard to keep out the interruptions. You could drop them a line afterwards, underlining a couple of points which you think may not have come across well because of the background noise.