Sometimes, what separates successful people from everyone else isn't what they say — it's what they don't say.

You might want to avoid jargon in the workplace: phrases like "ducks in a row" or "move the needle" that probably confuse your co-workers, according to research published by LinkedIn and Duolingo last year. Other sayings, like "keep me in the loop" or "just checking in," can unintentionally come across as passive-aggressive, Slack executive Jaime DeLanghe told CNBC Make It in 2022.

In particular, the best employees typically steer clear from these three phrases and sayings, according to CEOs, psychologists and linguistics experts:

'It is what it is'

There's one phrase bosses and colleagues don't want to hear when they're facing a problem at work: "It is what it is."

"People say it when, really, what they mean is, 'I don't care," John McWhorter, an author, linguist and associate professor at Columbia University, told Bill Gates' "Unconfuse Me" podcast last year. 

You've probably heard the phrase before, or used it yourself —perhaps in response to a dilemma or situation that can't be fixed and just has to be accepted. Using it, however, can appear highly passive to other people and tarnish their trust in you, McWhorter said.

Try swapping the phrase for something less dismissive, psychologist Cortney S. Warren told Make It last year: "I have to see reality for what it is, even if it's not what I want, so I can move forward."

'This is how we've always done it'

For Jason Buechel, CEO of Amazon-owned grocery chain Whole Foods, the biggest red flag in an employee is "somebody who thinks they know the answer to absolutely everything," he told Make It last month.

"I sometimes could have been that person in my past, on certain things," Buechel said. "And I learned the hard way that you have to be flexible, especially in today's world. Our customers' demands are changing all the time, things are always changing the business."

Executives from JPMorgan Chase CEO Jamie Dimon to Amazon CEO Andy Jassy say they value employees who are energized by learning new ideas and perspectives and find ways to apply them to the workplace. That means there's one sentence that can frustrate such CEOs: This is how we've always done it.

In contrast, staying curious and embracing new opportunities can help you stay engaged in your career and hobbies, make you happier and help you better manage your professional journey's twists and turns, research shows.

'I'll never be able to get this. Why bother?'

Everyone, at some point or another, is faced with a task that seems impossible. You may try to psych yourself out, telling yourself  "I'll never be able to get this. Why bother?"

In actuality, your brain "can continue to develop and change until old age," Emma Seppälä, a Yale lecturer and psychologist, wrote for Make It in April. "You can change careers at 50 and you can start playing the piano at 80. You can learn new things at any point and, with practice, you can get better at almost anything."

Instead of battering "I can't do this" into your brain, change your perspective and say, "I need more practice," Seppälä advised. Thinking about something you can do with ease, and then thinking back to the first time you did that thing, can help reassure you, she wrote.

"The same will be true of the thing you attempted for the first time today — if you keep trying," wrote Seppälä.

Want to stop worrying about money? Sign up for CNBC's new online course Achieve Financial Wellness: Be Happier, Wealthier & More Financially Secure. We'll teach you the psychology of money, how to manage your stress and create healthy habits, and simple ways to boost your savings, get out of debt and invest for the future. Start today and use code EARLYBIRD for an introductory discount of 30% off through September 2, 2024.

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