I had online interview, the interviewer joined late. At first the interview started well and interviewer asked fundamental question. But after sometime he started arguing without any point. He would interrupt everytime, when you are explaining a system design, and without listening whole thing and try to prove that he knows about it :D :D. When you come to a valid point which he has no knowledge about, he would just try to escape from the question and ask something else. Not that professional interviewer.