The interviewer is just an ordinary guy so don't feel in awe...it isn't necessary.
If you start changing your answers because the interviewer doesn't agree with you then you're not suitable. If you believe that your answer is correct hold your ground and explain why.
If you give a stupid answer expect to be led up the garden path. And if you realise that this is happening ' stop it by admitting that your earlier answer was wrong. Using candour may earn you a brownie point.
You aren't expected to answer everything correctly. Just be honest , open , candid and above all single minded.