Ego is a Good Thing. But the interviewers need to remember that interviewing a candidate is not about how great the interviewer is; it's about understanding what the candidate will be able to do for you at work. Thanks to Rohan Kini's “Scary interviews”, read Tips to technical interviewing.
I don't buy tip 4/5, where Vikram says to explain the process and questions, and not to start with the hardest question. “It depends.” If the hardest question is an elimination question, ask away. You don't have to explain your questions, but you should explain if you're asking a behavior-description question, so people can understand you're looking for specific examples.