After hiring over five hundred people and interviewing countless more, I've learned consistent patterns. People come in all shapes and sizes, but personalities and attitudes revealed during an interview can often times be very reliable indicators of future job performance. There are always the occasional surprises -- like the smashing interviewee who stalls out in their third month or the person having a bad day who performs like a superstar. Those outliers aside, I've been struck by the dependable consistency of interviewee behavior as an early indicator of what can be expected from a prospect should they be offered the position.

It is Simpler Than Looking Good

Many hopeful prospects dedicate much of their energy to polishing their appearance, asking the right questions, power-posing, maintaining good posture, smiling, trying to be like-able, and many other widely written about (and very important) aspects of how to nail an interview. This is the hard work of the job interview and the outcome can hinge on how well the candidate navigates these areas.

Still, there is one other sure-fire way to almost immediately dissuade an interviewer from wanting to continue. This one thing has proven again and again as the single most predictive red flag for a future "problem employee" in my experience. It's not asking about salary. And, it's not even texting. Of course, looking at an incoming text message during an interview can (at the very best) convey disinterest and asking about salary (if not done tactfully) can send the message that the interviewee is solely interested in what they can get and not what they can give an organization.

Interview Jitters May Actually Help You

Appearing nervous during the interview is also not the single worst thing an interviewee can do to lose an opportunity. In fact, sometimes, the opposite can be true when it comes to interview jitters. When a qualified and competent interviewee appears nervous, it can sometimes send a positive signal that he or she really desires to be part of the organization and doesn't want to risk missing their chance. It can be almost flattering to the person conducting the interview.

The Biggest Mistake

So, what is the one key to never getting called back by the employer ever again? Based on my experience, I believe that an interviewee who speaks negatively about a past or present employer is one of the most consistent markers of a future "problem employee."

When an interviewee passionately explains how they were the victim of mistreatment or unfair circumstances, they are forgetting the audience they are speaking to in the moment of the interview. They are not talking to a colleague or a friend. Instead, they are speaking to a senior level member of an organization (possibly a founding member) who has likely persevered through his or her own series of "unfair situations" and, instead of complaining, found a way to succeed in spite of many obstacles.

The interviewee will find no sympathy here. If the job candidate issues a series of complaints about a prior (or present day) employer, the insults and complaints stick to the interviewee; not to the former employer. Interestingly, the person conducting the interview may actually begin to feel empathetic to the employer being slandered as he or she can likely relate to them and their responsibilities more than they can relate to the person being interviewed. The senior level person conducting the interview may even feel a strong sense of comradery with the interviewee's current employer or supervisor and even find themselves siding with their position (whether they reveal it to the interviewee or not).

Make Others Look Good

Even if you feel you were unfairly treated or that you experienced the worst boss or co-workers imaginable in a prior setting, the best approach for an interviewee who is serious about landing the job is to point out the positives of a past work experience. Highlight the lessons learned and the good experiences; never, ever gossip or complain in an interview. Any hiring manager with experience knows that history often repeats itself with job candidates. The applicants who came to the interview complaining of "horrible co-workers" or "an unfair boss" will soon be in that same manager's office with a similar list of complaints. A good rule of thumb - if you can't be complimentary, just be quiet.