Sometimes we all need to hear “no”.

Imagine the millions of dollars that might have been saved if more underlings had been bold enough to speak up when they recognized an idea as bad. Imagine the embarrassments and lawsuits companies could have been spared if someone had been willing to call out the flaws in a plan or concept.

A meeting where everyone agrees is a pleasant meeting, and usually a short meeting. And who doesn’t like pleasant, short meetings?

But, when your meetings are 10 minutes long and everyone leaves with a smile on their face, you’ll likely have peace in the office—but you’ll also increase your chances of failing. Your organization may be staffed with likable, agreeable, good-hearted folks, but are you innovating? Are you growing? Are you spotting problems before they blindside you? For an organization to truly excel, the people in it need to feel comfortable voicing dissent.

In a recent blog post, Patrick Lencioni writes, “The practical advantage of diversity boils down to this: a group of people with different perspectives usually makes better decisions and finds more creative solutions than those who have largely similar views, backgrounds and skill sets.”

Lencioni isn’t only talking about diversity in the conventional sense, he doesn’t mean simply racial or gender diversity. He’s referring to diversity of thought and temperament. You’ve got to get people who view the world differently, and you’ve got to have an environment where they feel comfortable hashing out their thoughts.

President Abraham Lincoln famously assembled a team of rivals for his cabinet. The idea, and Lincoln was not the first president to adopt it, was that by having differing opinions from people with different perspectives, the President would be more likely to find wise solutions.

When the process turns contentious, resist the urge to be the peacemaker. Let the parties that disagree work through the disagreement. As each side argues their points, they’re more likely to discover the reasons why the other side thinks a certain way and when your end result is able to address those whys, your organization will function better.