In this day and age, where almost *everybody* has a Facebook account, it's quite possible that the interviewer thought you were simply lying about not having one because there was something on it that you didn't want him/her to see - there are quite a few employees who ask for Facebook logins as a screening mechanism. Given that you're statistically more likely to have a facebook and lie about not having one, than to truly not have one, more people will go with the statistic as Facebook has become *that* ingrained into our lives. As a fellow non-user of that website, I've run into a number of people - too many, IMO, who were literally astounded that I don't have a FB of my own. Frankly, I don't trust the company with my data. Your reasons may vary, but the results are all the same: you're looked upon with suspicion and disbelief for your choices. And that may cost you some semblance of "normalcy" which in this case, has cost you your potential job.