Don't be too surprised and if at some point during the interview and interviewer displays a bit of verbal aggression or asks a question that is seeming to want to provoke an argument with you. This is almost always an experienced interviewer's ruse to see how you cope in a conflict situation or with an aggressive person. Don't take it personally but instead realise that it is just a small test.
Maintain your even equilibrium, don't rise to the bait, but smile knowingly and answer the question calmly and politely. Make no reference to your understanding of what it is that they were trying to do. If you know that you have a sparkling sense of humour and you are able to think quickly enough under the circumstances, then this might be the best time to bring it to good use. Humour in the face of adversity is appreciated by almost everybody.