Being a leader in people-centric work cultures differs drastically from managers in toxic workplaces who bark out demands and use century-old tactics like fear and negative reinforcement to motivate.

Truly effective leaders get their people from the neck up through influence -- the positive actions that connect them with the people they lead. But for many of us, when we end up telling stories to our kids and grandkids about the leaders who made a difference in our lives, we remember the words they spoke.

Words can be memorable and create immense value for you, or they can leave you shaking your head in frustration. Here are three for each side of the coin.

3 Things Great Leaders Say

You may think a leader speaks with charisma and bravado. Perhaps, if on a stage presenting a product launch to an audience of 500 (for example, Steve Jobs). But in close teams and interpersonal interactions that build trust, authenticity wins out every time. Here's what you'll hear from the most effective and humble leaders. 

"That was my fault."

Great leaders put their ego aside, because admitting to being human and making mistakes actually increases trust. Paul Zak, author of Trust Factor: The Science of Creating High-Performance Companies, says, "People who are imperfect are more attractive to us. We like them more than people who seem too perfect." 

"I couldn't have done it without you."

This is quite possibly the highest form of saying thank you. By acknowledging someone else's effort for going above and beyond, a leader makes that person look good by shining the spotlight on their individual contributions, which he or she deserves. When reinforced as a cultural trait, this simple act of encouragement is mental booster that will send ripples of trust across the organization.

"Can I get your advice on this?"

A study conducted by researchers at Harvard Business School and the Wharton School linked people who ask for advice to being perceived as more competent. One of the study's authors, Alison Wood Brooks, says: "In our research, we find that people are hesitant to ask for advice because they are afraid they will appear incompetent." She says that this is misplaced fear. The reality is that "people view those who seek their advice as more competent than those who do not seek their advice."

3 Things Great Leaders Would Never Say

On the flip side, you'll most likely never find these words coming out of the mouths of confident and smart leaders. 

"That's not my problem." 

Hearing this shouted across the hall when you're asking for help or input on something important reveals an uncaring and detached attitude that screams "I'm not a team player." Granted, no one should jump and say yes just to please a colleague. If you don't have the time to deal with someone's request, articulate it tactfully and thoughtfully when expressing no in a way that doesn't make you look selfish or unconcerned. 

"I'm in charge."

If you have the need to tell others that you're in charge, chances are you're probably not. Bad leaders will use this phrase to instill fear in workers and establish positional authority, which is contrary to what great leaders do. By avoiding this phrase, leaders can begin the process of empowering their people to make decisions and own their work. And by doing so, they open up avenues for respect, loyalty, and commitment to take place.

"It's impossible."

This is the fast track to shutting down creativity and innovation in your knowledge workers. They look to their leaders for inspiration and the belief that anything is possible. That's why hearing these words is really an unfortunate self-fulfilling prophecy -- it sucks the air out of hopeful teams and thwarts any possibility for challenging projects to be accomplished. On the flip side, great leaders are absolutely confident in their people's abilities; they have an internal faith mechanism that will explore every avenue, solicit every opinion and input, and ask the question, "How can we, as a team, make this happen?"