Leaders must be tough.

Leaders must be demanding.

Leaders can’t show weakness.

There are many hard-shell qualities that uninformed people believe leaders need to possess. There are certainly times when a leader needs to show incredible strength and mental fortitude.

When a team needs a strong leader, most people don’t automatically picture someone being playful and even a little goofy at times. That just doesn’t feel dignified or “leader-like.”

Yet, exceptional leaders have proved otherwise.

Legendary co-founder and longtime CEO of Southwest Airlines, Herb Kelleher, promoted kindness over ego. With a tremendous sense of humor, a reputation for putting his employees first, and a steady commitment to loving people, Herb’s kindness made him one of the most respected and beloved leaders in business history.

When leaders believe they need to be tough as nails to show strength, it’s worth remembering that a man worth billions occasionally dressed as Elvis, just to bring joy to others.

His kindness didn’t make him a weak leader; it made him legendary.

No matter how successful someone hopes to become—or what words they want used to describe them—kind should always make the list.