Sabina Nawaz has been interviewing job candidates since her early days at Microsoft.

Nawaz worked at the company for 15 years, first as a software developer and then in HR, eventually working her way up to senior director of human resources. She left in 2005 and has since been coaching senior leaders on topics like negotiating conflict. Her book "You're the Boss," about becoming a better manager, comes out March 4.

Nawaz has seen some questionable behavior at job interviews. For example: "People who talk too much or people who talk too little," she says, explaining that "both ends of the spectrum are problematic." Then there are interviews that stand out for uniquely bizarre behavior.

Here's one of the worst interviews she's ever seen.

'They knew nothing about the job'

Early in her tenure at Microsoft, Nawaz was hiring for a specific role within software development. A candidate came in to interview who was clearly not qualified.

"They knew nothing about the job," she says, adding that "they just kind of had a blank stare most of the time." When the candidate did ask questions, it was often about how much of the basic duties of the job they'd actually have to do. They didn't inspire confidence that they could actually perform those duties.

It's quite possible the company didn't screen the candidate carefully enough to make sure they were a good fit, but the candidate also continued interviewing even after learning what the job would entail.

She was 'a little frustrated'

There were multiple problems with this interview.

First, Nawaz was "a little frustrated" that someone who was so obviously unqualified was there, she says. Second, in a moment when Microsoft genuinely needed to fill their opening, it "was not a great use of time" to talk to someone who just couldn't cut it.

Sometimes candidates aren't a good fit for one role but they could be for another. A recruiter won't always be able to catch this in an initial screener, but a candidate should speak up if they realize the job isn't close to the right match for their skills.

"If they had said, 'You know what, I think there was a disconnect,'" Nawaz says, she would have been grateful for their candor. "I would have had a lot of respect for that and I might even say, 'Well, what would be the right'" fit?

But the fact that they wasted her time and continued interviewing when it was clear to both sides they didn't have the chops to do the job meant that she wouldn't consider them for any other role — in that moment or any time down the line.

Nawaz just "tried to cut the interview as short as I could," she says.

It's OK to apply for an array of roles as a jobseeker, but if you see that one isn't a good fit during the interview process, be honest with yourself and forthcoming with your interviewer so that neither one of you is wasting your time.

Want to up your AI skills and be more productive? Take CNBC's new online course How to Use AI to Be More Successful at Work. Expert instructors will teach you how to get started, practical uses, tips for effective prompt-writing, and mistakes to avoid. Sign up now and use coupon code EARLYBIRD for an introductory discount of 30% off $67 (+ taxes and fees) through February 11, 2025.

Plus, sign up for CNBC Make It's newsletter to get tips and tricks for success at work, with money and in life.