These Quora-users confess to the wondrous ways in which they screwed up their interviews. Think of it as a "What not to do." Or just be grateful it wasn't you.
We've edited a few and excerpted them here.
It's probably best to let them ask the questions.
Prashant Tibrewal: I had my interview scheduled for Facebook at campus selections. I was excited and a bit nervous about the interview. As the interview started, the interviewer was telling a bit about what he was working on (just to make me comfortable). I got excited on that and kept asking questions about that for about 25 minutes.
And believe it or not that was the blunder I did because after those 25 minutes he asked me a question for which I figured out the algorithm fast but couldn't complete the code as the interview span was 50 mins. And hence I didn't even get to the second round.
And that was the day when I vowed to never ask my interviewer any question.
Carrying another company's bag is not the greatest idea.
Rajat Khandelwal: I cleared two (screening) rounds of Google interview and the third round was to be done in the Bangalore office. Just a couple days before the date I got a job offer from InMobi. Now before the Google Interview I knew I'd prefer working at InMobi even if I got an offer from Google. So I wasn't very tense about the interview.So on the day of interview, I went to their office and just as I reached there, I realized that the bag I had was the one I got from InMobi. I didn't think ahead and brought the bag. I don't know but I like to think that was one factor.
The interviewer asked a few questions which I answered as best as I could. And in the end I asked him this question:
"I've heard rumors that all good projects at Google are moved to MtV office so working at Google India is not as great as the name suggests. How true is that?"
And I realized very late that it was an inappropriate thing to ask. And even though my interview went great, my application was terminated at that level.
Don't bring in the competition.
Doug Luce: By pulling out an iPad mid-interview to Google the interviewer's question.
The guy became visibly agitated and told me I couldn't do that. The rest of the interview went downhill from there.
Don't not listen.
Pierce Wetter: ...At Google I was asked about A/B testing. Playing it back in my head I realize the interviewer was fishing for an answer with Chi2 or a T test .
I ignored that at the time because I don't believe in that type of analysis even though I know how to do it. I believe in: having a product vision, listening to your customers, and watching what they do and why. Choosing one layout over another based on a 52/48% split isn't product design. In fact it probably means you are either iterating on something that doesn't matter or don't understand the problem yet.
Put another way, statistics on user behavior can be a compass but it's not a map.
That all would have been a great thing to say in an interview (they might not have agreed but then I would know something too) but that's not what I said. Instead I just said I'd want to see 2x one vs the other.
Always be sure you're solution is correct.
Prakash Deivakani: I was interviewed by Ajay Somani of Facebook (Red in Topcoder). I was a grey coder by then.
I was asked to solve a problem on a board. I made a mistake and he asked, "Are you sure your solution is correct?" I figured out a mistake and corrected it. He again asked, "Are you sure your solution is correct?" I again found a mistake and corrected it. He again asked me, "Are you sure your solution is correct?" I was silent for a while. He told me, "Your solution is correct. You can wait outside."
Moral: Be quick, precise and confident
Get some sleep.
Nakul Agrawal: I was interviewing with Intel India Pvt. Ltd. and it was 5:30 AM in the morning and had just completed an interview with DirectI from 2 AM - 4 AM. And I had Nvidia coming up next morning at 10 AM.
Earlier that day I had given two written tests for DirectI (one of 1 hour and another of 3 hours). And yet there I was sitting in a black suit all ready for my interview at 5:30 AM.
You can imagine the stress and tiredness.
So I walk in, he asks me to sit down and asks my name. I give a fake smile and tell him my name. He then directly starts with the technical questions.
Interviewer: Can you write code for merge sort?
Me: Do you really want me to write the code for merge sort? Won't an explanation suffice? (I mean it is a well known algo! What can you possibly test by that?!)
Interviewer: Yes. Please write the code.
Me (writing on the paper) - void mergesort(int a[], int n) { }
Me: Do you really want me to write the code?
Interviewer: Yes
Me: I am not able to write it.
Interviewer (Smiles): Thanks. That will be enough.
...Now that's how you screw up interviews.