Applied different positions 2 months ago. Received an e-mail for setting up phone interview. Phone interview lasted an hour. Most of the questions were from my background and there was only a simple technical question or at least that's what I thought. Wrote the solution in under a minute. He kept asking more and more questions in detail also made me solve it using another way. I explained him how post increment works yet he just didn't understand and kept arguing. Finally, he noticed a bug which he didn't find at first look and his tone just went down. Overall this was a waste of time on my end with all the time I spent studying only to argue what I told was true. On the other hand the HR (for once) didn't keep me waiting for an answer more than a week.