I was contacted by a recruiter and set up a phone interview. There were two interviewers at the same time: one senior engineer and one engineer who had only been out of college for four months. The questions were very easy, but I had already had two other interviews that day and was quite tired. The younger engineer kept pushing me and talking all the time while I was coding, trying to show how knowledgeable he was. He interrupted me all the time, even when I called a helper function that I planned to implement later. I couldn't think under that situation and messed up the interview.

One week later, the recruiter called to inform me about the rejection while I was in a lecture.

It's not difficult if you're in a quiet environment.