'How much does an aeroplane weigh?'; 'Why are manhole covers round?'. Despite the popularity of bizarre questions like this in interviews for jobs in the big technology companies, they have been proved to give little insight into the applicant's ability or personality. Applicants faced with such questions would be well-advised to reconsider their interest in working for such companies. A study which investigated why these approaches persist concluded that these 'brainteaser' questions are popular with interviewers who like to protect and enhance their self-esteem by appearing to know the answers to impossibly difficult questions. They enjoy the feeling of power and superiority over the candidate, revealing a narcissistic or sadistic personality. No-one wants to work for someone like that.