Yeah. I bombed my first interview for a networking related job. I had done ISP tech support for about 3.5 years and thought I was ready to jump into the networking world.
Question 1: How many usable IP addresses do you get with a subnet mask of 255.255.255.252? My answer: 1 * My rationale: The way I learned it, 1 IP is taken by the ISP and the other IP is usable for the customer. Question 2: Have you ever heard of the OSI model? My answer: No
There were no more technical questions after that. I could tell I wasn't getting the job. After the interview was over, I sat in my car for about an hour outside the building and I was incredibly angry at myself for doing so poorly in the interview.
Years later I got my CCNA and went back and interviewed at that same company. I knocked the interview out of the park, but told them I didn't want the job. I just wanted to see how well I would do at that point.