By Contributor,Tomas Chamorro-Premuzic

Copyright forbes

Scientifically-derived lessons for avoiding common mistakes

Interview waiting room

“All the world is not, of course, a stage, but the crucial ways in which it isn’t are not easy to specify” Erwing Goffman

Despite its questionable utility, the job interview remains a near-universal vetting tool to differentiate between successful and unsuccessful candidates.

Nevermind that psychological assessment tools are faster, cheaper, and more accurate predictors of future job performance, or that AI can provide more reliable and valid ways to identify significant indicators of human potential while mitigating biases; the vast majority of hiring managers and recruiters would find it unthinkable to select a candidate without first subjecting them to an interview.

As I illustrate in my latest book, Don’t be yourself: Why authenticity is overrated and what to do instead, research provides a great deal of data on how to improve your performance on interviews. While popular discussions on the subject tend to focus on what to do, it is probably wiser to take into consideration what not to do, since the exclusion criteria are generally more clear-cut, and likely to generate consensus, than the selection criteria (not least since candidates are typically pre-screened and pre-selected by the time they are interviewed).

With that, here are five things you should NOT do during a job interview:

(1) Don’t FAKE it (unless you can BS yourself first): Some estimates suggest that up to 90% of candidates engage in some degree of faking during an interview,and there’s no certainty that they would be found out. That said, there is a high cost to being found out, and unskilled faking attempts are vulnerable to detection. For instance, if your smile is more “painted on” than genuine, or if you’re clearly parroting stock answers, you risk coming across as insincere. Research on surface acting shows that when people fake emotions they don’t feel, it not only drains them but also signals inauthenticity to others. The only way “faking it” works is if you also convince yourself — psychologists call this deep acting, aligning your internal state with the role you’re playing. In line, research shows that effective impression management during the interview is best interpreted, not as noise or false signal, but rather emotional intelligence or social skills. After all, people who convincingly fake being good candidates on an interview are more likely to convince their managers they are good employees after they are hired.

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(2) Shut up and listen (unless you are asked to talk): Many candidates fall into the trap of over-talking (often a sign of insecurity, and at times just narcissism!), turning a structured dialogue into a monologue. But interviews are as much about showing your listening skills as your speaking skills. Studies on impression management show that monopolizing airtime leads to lower ratings because it signals arrogance or lack of social awareness. A well-timed pause or a clarifying question often makes you look more thoughtful and engaged than another five-minute spiel about your “passion.”

(3) Don’t disparage people (especially past colleagues or bosses): You may think that bad-mouthing your old boss demonstrates honesty, but interviewers usually read it as bitterness, poor teamwork, or a lack of discretion. Research on influence tactics shows that negative talk is one of the fastest ways to undermine perceptions of agreeableness and fit. Even if your ex-manager was truly toxic, the safe move is to frame the experience as a learning opportunity. Otherwise, you signal that you might be the “toxic” one. For all the potential value that misfits can add to a team or organization, the reality is that most hiring managers and companies would rather higher on culture-fit, and candidates who feel comfortable to criticize their past coworkers or bosses will likely be perceived as a threat to the status-quo.

(4) Don’t appear unprepared (especially if you are): Winging it might work for improv comedy, but not for job interviews. Hiring managers can tell when you haven’t done your homework, and lack of preparation screams low conscientiousness. Meta-analytic evidence shows that structured preparation — researching the role, tailoring your answers, knowing the company — strongly predicts better evaluations. Coming in clueless makes you look either uninterested or arrogant, both of which kill your chances.

(5) Don’t suck up (too much): A little appreciation for the company or interviewer can show warmth, but overdoing it edges into obsequiousness. Excessive flattery triggers suspicion: if you’re laying it on this thick now, what will you be like once you’re hired? Research on ingratiation tactics finds that modest doses can help, but when overused they reduce credibility and make candidates appear manipulative. The line between “enthusiastic” and “sycophantic” is thinner than you think.

In the end, the interview remains a curious paradox: an imperfect ritual that endures because it feels indispensable. Candidates may not be able to control every outcome, but they can avoid the most obvious self-inflicted wounds. If faking falls flat, rambling signals arrogance, badmouthing betrays bitterness, poor preparation looks careless, and over-flattery reeks of manipulation, then the safest strategy is disciplined restraint. What you don’t do may matter as much as what you do. In a setting where impressions harden quickly and missteps linger, the wisest move is to project competence without undermining yourself.

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