Every great leader I’ve ever met has one thing in common. They differ in backgrounds, experiences, skills, giftedness, personality types, field of study, and every other area imaginable. Leaders come in all different shapes and sizes. Some lead Fortune 500 companies and others only have a single line on their resume which reads “Stay-at-Home Mom.”

But every great leader shares one common trait—they want to know more about leadership.

I’ve never met a truly effective know-it-all leader.

They don’t exist. (See: You Control What Matters Most)

Their self-evaluation of perfection keeps them from ever serving others in a way which makes them effective.

Great leaders know they don’t know it all. And because they don’t know it all, they are always looking to learn from others.

Soon after graduate school, I found myself teaching a group of men of various ages. From long-time retired to early in their career, these men gathered every Wednesday learning to learn how to be better husbands, fathers, leaders, and men. I didn’t start the class, but for a semester I was asked to teach it. (See: What No One Ever Tells You About Being a Leader)

I was extremely intimidated. How would I teach a group of men who were all older than me on issues which confront men?

The material was good; I had no doubt it could influence the learners. My fear was my credibility. How could I teach in a credible way.

One Wednesday after class, I was speaking to a friend about my uncomfortableness and he said, “Kevin, the only one in that class uncomfortable with your age is you. The rest of us just want to learn. We don’t care how old the teacher is as long as the material is useful to our lives.”

That day my friend told me not just the perspective of a good man, but the perspective of a great leader.

Great leaders think differently than most people.

Most people only learn from “experts.” They have to believe the other person is much more knowledgeable in every area of life in order to learn from them. Like a fourth-grader who assumes he is smarter than every person in the grade below him, most people believe they can only learn from a few known experts.

Most people only learn from others in their same field. It is a rare person who is able to see parallels in various fields and can gain information from other areas of study. The average person can only see lessons which directly apply to their concern. (See: 7 Leadership Lessons from Gus Malzahn)

Most people only learn at limited times. The average person doesn’t read a book after college much less a book a month or a book a week. They only study when there is a specific piece of information they need to learn.

Contrast this way of thinking with how great leaders think.

Great leaders can learn from anyone. While they might gain more from other great leaders, they have the ability to learn from anyone. True leaders can take the beliefs, ideas, insights, and example from other people and gain insight into their own situations. Whether someone is good or bad, they can make a great leader better. (See: 8 Leadership Lessons Ella Taught Me in her First 8 Years)

Great leaders intentionally learn across fields of study. They know some of the greatest learning opportunities come from people in other area of expertise. Sometimes, by looking in a different field, a leader can focus less on the details and more on the big picture.

Great leaders are always learning. There is never a moment in which they are not learning. While an average person only learns when they recognize an area where knowledge is needed, a great leader is learning skills before they even know if it will be needed. They are always learning new ideas and skills knowing that knowledge is never wasted. Whatever can be learned today will be used tomorrow.

Leaders are as diverse and unique as the world in which we live. There are very few things which all great leaders have in common. But the awareness that they need to learn and an engagement in the learning process is universally true for every great leader.